US20090238299A1 - Detecting the Number of Transmit Antennas in Wireless Communication Systems - Google Patents
Detecting the Number of Transmit Antennas in Wireless Communication Systems Download PDFInfo
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- US20090238299A1 US20090238299A1 US12/469,323 US46932309A US2009238299A1 US 20090238299 A1 US20090238299 A1 US 20090238299A1 US 46932309 A US46932309 A US 46932309A US 2009238299 A1 US2009238299 A1 US 2009238299A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2602—Signal structure
- H04L27/261—Details of reference signals
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/02—Arrangements for detecting or preventing errors in the information received by diversity reception
- H04L1/06—Arrangements for detecting or preventing errors in the information received by diversity reception using space diversity
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/0212—Channel estimation of impulse response
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2602—Signal structure
- H04L27/261—Details of reference signals
- H04L27/2613—Structure of the reference signals
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W99/00—Subject matter not provided for in other groups of this subclass
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
- H04B7/0667—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of delayed versions of same signal
- H04B7/0671—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of delayed versions of same signal using different delays between antennas
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/02—Arrangements for detecting or preventing errors in the information received by diversity reception
- H04L1/06—Arrangements for detecting or preventing errors in the information received by diversity reception using space diversity
- H04L1/0618—Space-time coding
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/0224—Channel estimation using sounding signals
- H04L25/0226—Channel estimation using sounding signals sounding signals per se
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
- H04W16/14—Spectrum sharing arrangements between different networks
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W24/00—Supervisory, monitoring or testing arrangements
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W84/00—Network topologies
- H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
- H04W84/10—Small scale networks; Flat hierarchical networks
- H04W84/12—WLAN [Wireless Local Area Networks]
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/02—Terminal devices
- H04W88/06—Terminal devices adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
Definitions
- Data is often encoded at the transmitter, in a controlled manner, to include redundancy.
- the redundancy is subsequently used by the receiver to overcome the noise and interference introduced in the data while being transmitted through the channel.
- the transmitter might encode k bits with n bits where n is greater than k, according to some coding scheme.
- the amount of redundancy introduced by the encoding of the data is determined by the ratio n/k, the inverse of which is referred to as the code rate.
- the transmitter includes multiple transmit antennas and the receiver includes multiple receive antennas.
- a MIMO system is typically used to increase the data rate, diversity, or a combination thereof.
- the increase in data rate is achieved by transmitting multiple data streams via the multiple transmit antennas, also known as spatial multiplexing.
- the diversity is achieved by increasing the redundancy between the transmit antennas through joint coding.
- the IEEE 802.11a standard defines data rates of 6 Mbps (megabits per second) up to 54 Mbps. For some applications, higher data rates for given modulations and data rates higher than 54 Mbps are desirable. Other extensions, such as the use of MIMO systems and other extensions might be desirable. In order to avoid conflicts with existing standardized communications and devices, extended devices that extend beyond the limits of the 802.11a standard and legacy devices that comply with the existing standard and are not necessarily aware of extended standards both need to coexist in a common communication space and interoperate at times.
- Coexistence occurs where different devices can operate in a common space and perform most of their functions.
- an extended transmitter transmitting to an extended receiver might coexist with a legacy transmitter transmitting to a legacy receiver, and the extended devices can communicate while the legacy devices communicate, or at least where the two domains are such that one defers to the other when the other is communicating.
- Coexistence is important so that the adoption and/or use of extended devices (i.e., devices that are outside, beyond or noncompliant with one or more standards with which legacy devices adhere and expect other devices to adhere) do not require replacement or disabling of existing infrastructures of legacy devices.
- an extended transmitter might initiate a transmission in such a manner that a legacy device can receive the data sent by the extended transmitter and/or indicate that it is a legacy device so that the extended transmitter can adjust its operations accordingly.
- the extended transmitter might revert to standards compliant communications or switch to a mode that, while not fully standards compliant, is available to the legacy receiver.
- an extended receiver might successfully receive data from a legacy transmitter.
- the IEEE 802.11a standard defines a 20 microsecond long preamble with a structure as shown in FIG. 1 , having short training symbols S (0.8 microseconds each), a guard interval LG, long training symbols L (3.2 microseconds each) and a signal field (4 microseconds).
- the preamble is followed by data.
- the first eight microseconds include ten identical short training symbols that are used for packet detection, automatic gain control and coarse frequency estimation.
- the second eight microseconds include two identical long training symbols, L, preceded by a guard interval LG that is the same pattern as the last half (1.6 microseconds) of the long training symbol L.
- the long training symbols can be used for channel estimation, timing, and fine frequency estimation.
- FIG. 2 shows a long training sequence, L 1 , that is used to generate the signal representing the long training symbol in a conventional 802.11a preamble.
- This sequence represents values used over a plurality of subcarriers.
- the subcarriers span a 20 MHz channel and with 64 subcarriers, they are spaced apart by 312.5 kHz.
- the 33rd value corresponds to the ⁇ 10 MHz subcarrier, followed by the ⁇ (10 MHz ⁇ 312.5 kHz) subcarrier, and so on, with the 64 value being for the ⁇ 312.5 kHz subcarrier.
- the DC value and the 28th through 38th values, corresponding to the edges of the 20 MHz channel, are zero.
- MIMO channels where a plurality of transmitters transmit different data or the same data separated by space to result in possibly different multi-path reflection characteristics.
- each of a number of preambles is adapted to be used in packets sent over a wireless network, such as an 802.11a compliant wireless network, to enable detection of the number of transmit antennas.
- Packets containing preambles of the present invention may be received by extended devices as well as by legacy receivers that are not configured to receive and interpret these preambles.
- the detection of the number of transmit antennas provides a number of advantages, such as enabling the estimation of the MIMO channel, synchronization of various transmitters and/or receivers, management of the application of power to various components disposed in the transmitters/receivers, and allocation of memory as well as other resource between various components of the receiver/transmitters.
- extended-long training (ELT) symbols disposed in the preamble are cyclically-shifted ELT symbols and transmitted on different transmit antennas.
- RX receiver
- a sum of shifted channel impulse responses corresponding to the channels from the different TX antennas is attained.
- the time shift associated with the channel impulse response at the receiver indicates the number of times the ELT symbols are cyclically shifted and thus represent the number of transmit antennas. In other words, by detecting the number of shifts; in the channel impulse response at the receiver, the number of TX antennas is estimated.
- the ELT symbols may be selected to be the same as the 802.11a long training symbols, but other long training symbols such as long training symbols where, next to the 802.11a subcarriers, the out-of-band tones, i.e., the 28th through 38th subcarriers are disposed, may be used.
- a fast Fourier transform (FFT) operation is performed on the received samples of the transmitted ELT symbols.
- FFT fast Fourier transform
- each subcarrier y q (i) is multiplied with the associated subcarrier frequency-domain representation of the ELT symbol with a cyclic shift of zero so as to remove the effect of the ELT and obtain a frequency-domain representation of the sum of shifted impulse responses.
- inverse Fourier transform or least squares (LS) operation is performed on the multiplied values to compute the transmission channel impulse response.
- the LS operation may be employed when fewer than all the tone of the ELT are used.
- the channel impulse response includes a sum of cyclically shifted impulse responses corresponding to the multiple transmit antennas.
- the number of cyclically shifted impulse responses in the channel impulse response represents the number of transmit antennas.
- FIG. 1 shows the preamble of a conventional 802.11a standard, as known in the prior art.
- FIG. 2 shows the frequency domain symbols of a long training symbol sequence starting with the DC subcarrier used in the 802.11a preamble of FIG. 1 , as known in the prior art.
- FIG. 3 shows a number of devices coupled via a wireless network.
- FIG. 4A is a plot of the absolute values of the channel impulse response of a two-transmitter system, determined in accordance with one embodiment of the present invention.
- FIG. 4B is a plot of the real parts of a window integration of the powers of the values used in FIG. 4A , in accordance with one embodiment of the present invention.
- FIGS. 5A , 5 B and 5 C show modified preambles with cyclic shifts adapted to be used by a receiver of a communication system having a multitude of transmit antenna systems to detect the number of transmitters of such a system, in accordance with one embodiment of the present invention.
- FIG. 6 is a flow-chart of steps used to detect the number of transmit antennas of a communication system having a multitude of transmit antennas, in accordance with one embodiment of the present invention.
- each of a number of preambles is adapted to be used in packets sent over a wireless network, such as an 802.11a compliant wireless network, to enable detection of the number of transmit antennas.
- Packets containing preambles of the present invention may be received by extended devices as well as by legacy receivers that are not configured to receive and interpret these preambles.
- the detection of the number of transmit antennas provides a number of advantages, such as enabling the estimation of the MIMO channel, synchronization of various transmitters and/or receivers, management of the application of power to various components disposed in the transmitters/receivers, and allocation of memory as well as other resource between various components of the receivers/transmitters.
- MIMO multiple-input single-output
- extended-long training (ELT) symbols disposed in the preamble are cyclically-shifted ELT symbols and transmitted on different transmit antennas.
- RX receiver
- a sum of shifted channel impulse responses corresponding to the channels from the different TX antennas is attained.
- the time shift associated with the channel impulse response at the receiver indicates the number of times the ELT symbols are cyclically shifted and thus represent the number of transmit antennas. In other words, by detecting the number of shifts in the channel impulse response at the receiver, the number of TX antennas is estimated.
- FIG. 3 shows an exemplary wireless network used for communications among transmitters and receivers as indicated.
- two wireless devices 1021 , 1022 might use and interpret the modified preambles, while a legacy wireless device 104 might not be expecting the modified preambles, but might hear signals representing such preambles.
- Extended wireless devices 102 might operate using multiple channels and/or multiple transmit antennas and/or multiple receive antennas. While separate transmit and receive antennas are shown, antennas might be used for both transmitting and receiving in some devices.
- Border 106 is not a physical border, but is shown to represent a space within which signals can be received from devices within the space. Thus, as one device transmits a signal representing a packet within border 106 , other devices within border 106 pick up the signals and, as they are programmed, will attempt to determine if the signals represent packets and if so, then demodulate/decode the packets to obtain the transmitted data.
- the algorithm adapted to detect the number of transmit antennas is described below with reference to a preamble with ELT symbols that are cyclically-shifted and transmitted from each of the transmit antennas of the MIMO system.
- the ELT symbols of the preamble are first transmitted from a first one of the transmit antennas and are thereafter cyclically-shifted the same number as the number of remaining transmit antennas of the MIMO system and subsequently transmitted from each such transmit antenna. It is understood, however, that the algorithm may also be applied to other training symbols.
- a fast Fourier transform (FFT) operation is performed on the received samples of the transmitted ELT symbols.
- r q (n) represents the n-th received time-domain sample on the q-th receive antenna.
- each subcarrier y q (i) is multiplied with the associated subcarrier frequency-domain representation of the ELT symbol so as to remove the effect of the ELT and to maintain the channel information.
- x p (i) is the frequency-domain representation of the training symbol on subcarrier i and transmit antenna p (or spatial stream p).
- N s N t
- the present invention may be readily applied to more general space-time-frequency mappings where the N s spatial streams are not directly mapped to the N t transmit antennas.
- the training symbol is assumed to be a known reference to both the transmitter and receiver.
- no cyclic shift is applied to transmit antenna 1 . Accordingly, the received frequency-domain information is multiplied by the conjugate of x 1 (i) to obtain the following:
- f(*) denotes the complex conjugation operation.
- x p (i) utilizes all subcarriers.
- IFFT inverse FFT
- C 2 is a normalization constant
- equation (3) may be rewritten as shown below:
- h f — qp (n) is the time-domain representation of the communication channel between transmitter p and receiver q, in other words, the impulse response of the communication channel between transmitter p and receiver q, and sp denotes the cyclic shift in samples applied to the p-th transmit antenna.
- C 3 is a normalization constant.
- cyclic window integration may be applied. Assume w(n) represents a window of N w samples long. Accordingly, a cyclic window integration over the power of r′ q (n), i.e.,
- 2 , with n 0, 1, . . . N c ⁇ 1, yields the following:
- mod is the modulo operator. It is understood that instead of using power of r′ q (n) in the above equation, one may use, for example, the amplitude of r′ q (n) or any other suitable measure.
- the maximum values meeting defined criteria in the intervals of expression (5) indicate the presence or absence of impulse responses in these intervals. The intervals are selected so as to match the various expected cyclic shifts of the ELT symbols.
- the following is an exemplary pseudo-code adapted to detect the number of transmit antennas of a MIMO system by determining the presence of maximum values in the various intervals associated with the cyclic integration windows, as defined in expression (5) above.
- the exemplary pseudo-code below assumes that the MIMO system includes no more than four transmit antennas. It is understood, however, that the following pseudo-code may be readily modified to detect the number of transmit antennas in a MIMO system having any number of transmit antennas. Assume that ⁇ M1, M2, . . . , M6 ⁇ represent the maximum values in each of intervals ⁇ I1, I2, . . . , I6 ⁇ as shown in FIG. 4B for this example. Accordingly, the number of transmit antennas is detected as shown below:
- parameters THR1, THR2 and THR3 represent adjustable threshold values that may vary with the noise power.
- An estimate of the noise power may be obtained by subtracting the received samples corresponding to two (or more) subsequent equivalent training symbols and calculating the power of the result.
- Lines 1-4 of the above pseudo-code determine the maximum values that are above the designated threshold values(s) or noise floors.
- Lines 5-6 defining the second comparison rule, are used to verify whether certain peaks are above a higher threshold, thus ensuring that even if the peak (maximum) values are below the noise floor, the correct number of transmit antennas is detected.
- Lines 7-8 are used to distinguish between three TX and four TX case because for high delay spread cases in the event the first two comparison rules fail.
- Lines 9-12 defining the fourth comparison rule, are used to ensure that the highest and the lowest peak values are within a certain range (e.g., 15 or 20 dB). This is particularly important to distinguish between the one TX and two TX cases.
- the cyclic shift of the ELT symbol at the first TX antenna is 0 samples and that at the second TX antenna is 32 samples at a sampling rate of 20 MHz or, equivalently, 1.6 ⁇ s.
- the shifts may be, e.g., 0, 21, and 42 samples; when there are four transmit antennas, the shifts may be, e.g., 0, 16, 32, and 48 samples, respectively, as understood by those skilled in the art.
- the absolute values of the complex numbers of the two TX channel impulse response is used in the plot of FIG. 4B .
- equation (5) for a window of 4 samples, integrating the square powers of the values shown in FIG. 4A results in the real parts as shown in FIG. 4B . Therefore, as described above, equation (5) may be used after equation (4) to improve the accuracy of the detection.
- FIGS. 5A , 5 B and 5 C respectively show cyclically shifted preambles adapted for transmission from systems having respectively 2, 3 and 4 transmit antennas.
- a sequence in the frequency domain is expressed with uppercase letters (e.g., L(i)), while the corresponding time sequence is expressed with lowercase letters (e.g., l(i)).
- the preambles which enable or enhance coexistence of MIMO packets in legacy devices include a cyclic delay shift applied to the ELT as well as Signal field prior to applying the guard time extension.
- L(i) and D(i) are the 64 subcarrier values for the ELT and Signal field symbols, respectively.
- the time samples for the long training symbol are derived by taking the 64-point IFFT of L(i) to obtain l(n) and transmitting the samples of l(n).
- the ELT symbol and guard time are constructed as [l(32:63) l(0:63) l(0:63)], i.e., the IFFT output is repeated twice and the last 32 samples are prefixed to form the long training guard interval.
- the long training guard interval (32 samples) is twice as long as the guard interval for 802.11a data symbols (16 samples).
- the signal field is formed by [d(48:63) d(0:63)], where d(0:63) are the 64 samples of the IFFT of D(i).
- the first transmitter transmits the long training symbol and signal field, as is the case with an of 802.11a transmission.
- one 3.2 microsecond repetition of the long training symbol L as shown in FIG. 1 is expressed in the time domain as the IFFT of L(i), where L(i) contains 64 subcarrier values, of which 52 are non-zero.
- the time samples l(n) are given as shown in equation (6):
- L(i) may contain more than 52 non-zero subcarriers.
- l(n) may have a cyclic shift that may be different for each transmitter.
- An alternative method of generating the cyclic shift is to apply a phase ramp rotation to all subcarrier values of L(i) prior to calculating the IFFT, such as that shown in equation (7) below:
- cyclic delay values s k may be 0 and 32 samples, respectively, corresponding to a cyclic delay of 1.6 microseconds between the two transmitters.
- s k may be 0, 21, and 42 samples, respectively.
- s k may be 0, 16, 32, and 48 samples, respectively.
- FIG. 6 shows a flowchart 600 of steps carried out to detect the number of transmit antennas.
- the process starts at step 602 .
- the transmitted ELT symbols are received.
- an FFT operation is performed on the received samples of the transmitted ELT symbols, possibly averaged over the two consecutive ELT symbols.
- the FFT values are multiplied with known frequency-domain representation of the training symbols on each sub-carrier of the reference transmit antenna, herein assumed transmit antenna 1 .
- an inverse FFT or LS estimate is performed on the multiplied results to transform the frequency domain values of equation (2) into time domain values.
- the number of shifted impulse responses in the channel impulse response are isolated to determine the number of transmit antennas.
- the process ends at step 614 .
- the above embodiments of the present invention are illustrative and not limiting. Various alternatives and equivalents are possible.
- the invention is not limited by the type of encoding, decoding, modulation, demodulation, equalization, filtering, etc., performed.
- the invention is not limited to the number of transmit or receive antennas.
- the invention is not limited by the rate used to transfer the data.
- the invention is not limited by the type of integrated circuit in which the present disclosure may be disposed.
- any specific type of process technology e.g., CMOS, Bipolar, or BICMOS that may be used to manufacture the present disclosure.
- Other additions, subtractions or modifications are obvious in view of the present disclosure and are intended to fall within the scope of the appended claims.
Abstract
Description
- The present application claims benefit under 35 USC 119(e) of U.S. provisional application No. 60/575,608, attorney docket number 021245-003200US, filed May 27, 2004, entitled “MODIFIED PREAMBLE STRUCTURE FOR IEEE 820.11A EXTENSIONS AND DETECTING THE NUMBER OF TRANSMIT ANTENNAS IN MIMO OR MISO COMMUNICATION SYSTEMS”, the content of which is incorporated herein by reference in its entirety.
- The present application is also related to co-pending U.S. application Ser. No. 10/820,440, filed Apr. 5, 2004, Attorney Docket No. 021245-001410US, entitled “MODIFIED PREAMBLE STRUCTURE FOR IEEE 802.11A EXTENSIONS TO ALLOW FOR COEXISTENCE AND INTEROPERABILITY BETWEEN 802.11A DEVICES AND HIGHER DATA RATE, MIMO OR OTHERWISE EXTENDED DEVICES”, the contents of which is incorporated herein by reference in its entirety.
- Demand for wireless digital communication and data processing systems is on the rise. Inherent in most digital communication channels are errors introduced when transferring frames, packets or cells containing data. Such errors are often caused by electrical interference or thermal noise. Data transmission error rates depend, in part, on the medium which carries the data. Typical bit error rates for copper based data transmission systems are in the order of 10−6. Optical fibers have typical bit error rates of 10−9 or less. Wireless transmission systems, on the other hand, may have error rates of 10−3 or higher. The relatively high bit error rates of wireless transmission systems pose certain difficulties in encoding and decoding of data transmitted via such systems. Partly because of its mathematical tractability and partly because of its application to a broad class of physical communication channels, the additive white Gaussian noise (AWGN) model is often used to characterize the noise in most communication channels.
- Data is often encoded at the transmitter, in a controlled manner, to include redundancy. The redundancy is subsequently used by the receiver to overcome the noise and interference introduced in the data while being transmitted through the channel. For example, the transmitter might encode k bits with n bits where n is greater than k, according to some coding scheme. The amount of redundancy introduced by the encoding of the data is determined by the ratio n/k, the inverse of which is referred to as the code rate.
- In a multiple-input multiple-output (MIMO) system, the transmitter includes multiple transmit antennas and the receiver includes multiple receive antennas. A MIMO system is typically used to increase the data rate, diversity, or a combination thereof. The increase in data rate is achieved by transmitting multiple data streams via the multiple transmit antennas, also known as spatial multiplexing. The diversity is achieved by increasing the redundancy between the transmit antennas through joint coding.
- The IEEE 802.11a standard defines data rates of 6 Mbps (megabits per second) up to 54 Mbps. For some applications, higher data rates for given modulations and data rates higher than 54 Mbps are desirable. Other extensions, such as the use of MIMO systems and other extensions might be desirable. In order to avoid conflicts with existing standardized communications and devices, extended devices that extend beyond the limits of the 802.11a standard and legacy devices that comply with the existing standard and are not necessarily aware of extended standards both need to coexist in a common communication space and interoperate at times.
- Coexistence occurs where different devices can operate in a common space and perform most of their functions. For example, an extended transmitter transmitting to an extended receiver might coexist with a legacy transmitter transmitting to a legacy receiver, and the extended devices can communicate while the legacy devices communicate, or at least where the two domains are such that one defers to the other when the other is communicating. Coexistence is important so that the adoption and/or use of extended devices (i.e., devices that are outside, beyond or noncompliant with one or more standards with which legacy devices adhere and expect other devices to adhere) do not require replacement or disabling of existing infrastructures of legacy devices.
- Interoperability occurs where an extended device and a legacy device can communicate. For example, an extended transmitter might initiate a transmission in such a manner that a legacy device can receive the data sent by the extended transmitter and/or indicate that it is a legacy device so that the extended transmitter can adjust its operations accordingly. For example, the extended transmitter might revert to standards compliant communications or switch to a mode that, while not fully standards compliant, is available to the legacy receiver. In another situation, an extended receiver might successfully receive data from a legacy transmitter.
- The IEEE 802.11a standard defines a 20 microsecond long preamble with a structure as shown in
FIG. 1 , having short training symbols S (0.8 microseconds each), a guard interval LG, long training symbols L (3.2 microseconds each) and a signal field (4 microseconds). The preamble is followed by data. The first eight microseconds include ten identical short training symbols that are used for packet detection, automatic gain control and coarse frequency estimation. The second eight microseconds include two identical long training symbols, L, preceded by a guard interval LG that is the same pattern as the last half (1.6 microseconds) of the long training symbol L. The long training symbols can be used for channel estimation, timing, and fine frequency estimation. -
FIG. 2 shows a long training sequence, L1, that is used to generate the signal representing the long training symbol in a conventional 802.11a preamble. This sequence represents values used over a plurality of subcarriers. As specified in the standard, the subcarriers span a 20 MHz channel and with 64 subcarriers, they are spaced apart by 312.5 kHz. By convention, used here, the first value in the sequence is the value for the DC subcarrier, followed by the value for the 1×312.5 kHz subcarrier, then the value for the 2×312.5=625 kHz subcarrier, etc., up to the 32nd value for the 31×312.5 kHz=9687.5 kHz subcarrier. The 33rd value corresponds to the −10 MHz subcarrier, followed by the −(10 MHz −312.5 kHz) subcarrier, and so on, with the 64 value being for the −312.5 kHz subcarrier. As can be seen fromFIG. 1 , the DC value and the 28th through 38th values, corresponding to the edges of the 20 MHz channel, are zero. - One approach to obtaining higher data rates is the use of more bandwidth. Another approach, used by itself or as well as the use of more bandwidth, is MIMO channels, where a plurality of transmitters transmit different data or the same data separated by space to result in possibly different multi-path reflection characteristics. When using MIMOs or MISOs, a number of advantages are gained by detecting the number of transmit antennas at the receiver.
- In accordance with one embodiment of the present invention, each of a number of preambles is adapted to be used in packets sent over a wireless network, such as an 802.11a compliant wireless network, to enable detection of the number of transmit antennas. Packets containing preambles of the present invention may be received by extended devices as well as by legacy receivers that are not configured to receive and interpret these preambles. The detection of the number of transmit antennas provides a number of advantages, such as enabling the estimation of the MIMO channel, synchronization of various transmitters and/or receivers, management of the application of power to various components disposed in the transmitters/receivers, and allocation of memory as well as other resource between various components of the receiver/transmitters.
- In one embodiment, extended-long training (ELT) symbols disposed in the preamble are cyclically-shifted ELT symbols and transmitted on different transmit antennas. At the receiver (RX), if the received symbols are detected as matching the known ELT symbols, a sum of shifted channel impulse responses corresponding to the channels from the different TX antennas is attained. The time shift associated with the channel impulse response at the receiver indicates the number of times the ELT symbols are cyclically shifted and thus represent the number of transmit antennas. In other words, by detecting the number of shifts; in the channel impulse response at the receiver, the number of TX antennas is estimated. The ELT symbols may be selected to be the same as the 802.11a long training symbols, but other long training symbols such as long training symbols where, next to the 802.11a subcarriers, the out-of-band tones, i.e., the 28th through 38th subcarriers are disposed, may be used.
- To detect the number of transmit antennas at the receiver, a fast Fourier transform (FFT) operation is performed on the received samples of the transmitted ELT symbols. Next, each subcarrier yq(i) is multiplied with the associated subcarrier frequency-domain representation of the ELT symbol with a cyclic shift of zero so as to remove the effect of the ELT and obtain a frequency-domain representation of the sum of shifted impulse responses. Next, inverse Fourier transform or least squares (LS) operation is performed on the multiplied values to compute the transmission channel impulse response. The LS operation may be employed when fewer than all the tone of the ELT are used. The channel impulse response includes a sum of cyclically shifted impulse responses corresponding to the multiple transmit antennas. The number of cyclically shifted impulse responses in the channel impulse response represents the number of transmit antennas.
-
FIG. 1 shows the preamble of a conventional 802.11a standard, as known in the prior art. -
FIG. 2 shows the frequency domain symbols of a long training symbol sequence starting with the DC subcarrier used in the 802.11a preamble ofFIG. 1 , as known in the prior art. -
FIG. 3 shows a number of devices coupled via a wireless network. -
FIG. 4A is a plot of the absolute values of the channel impulse response of a two-transmitter system, determined in accordance with one embodiment of the present invention. -
FIG. 4B is a plot of the real parts of a window integration of the powers of the values used inFIG. 4A , in accordance with one embodiment of the present invention. -
FIGS. 5A , 5B and 5C show modified preambles with cyclic shifts adapted to be used by a receiver of a communication system having a multitude of transmit antenna systems to detect the number of transmitters of such a system, in accordance with one embodiment of the present invention. -
FIG. 6 is a flow-chart of steps used to detect the number of transmit antennas of a communication system having a multitude of transmit antennas, in accordance with one embodiment of the present invention. - In accordance with one embodiment of the present invention, each of a number of preambles is adapted to be used in packets sent over a wireless network, such as an 802.11a compliant wireless network, to enable detection of the number of transmit antennas. Packets containing preambles of the present invention may be received by extended devices as well as by legacy receivers that are not configured to receive and interpret these preambles. The detection of the number of transmit antennas provides a number of advantages, such as enabling the estimation of the MIMO channel, synchronization of various transmitters and/or receivers, management of the application of power to various components disposed in the transmitters/receivers, and allocation of memory as well as other resource between various components of the receivers/transmitters. The following description is provided with reference to MIMO systems, however, it is understood that the invention equally applies to the multiple-input single-output (MISO) systems.
- In accordance with some embodiments of the present invention, extended-long training (ELT) symbols disposed in the preamble are cyclically-shifted ELT symbols and transmitted on different transmit antennas. At the receiver (RX), if the received symbols are detected as matching the known ELT symbols, a sum of shifted channel impulse responses corresponding to the channels from the different TX antennas is attained. The time shift associated with the channel impulse response at the receiver indicates the number of times the ELT symbols are cyclically shifted and thus represent the number of transmit antennas. In other words, by detecting the number of shifts in the channel impulse response at the receiver, the number of TX antennas is estimated.
-
FIG. 3 shows an exemplary wireless network used for communications among transmitters and receivers as indicated. As shown, two wireless devices 1021, 1022 might use and interpret the modified preambles, while alegacy wireless device 104 might not be expecting the modified preambles, but might hear signals representing such preambles.Extended wireless devices 102 might operate using multiple channels and/or multiple transmit antennas and/or multiple receive antennas. While separate transmit and receive antennas are shown, antennas might be used for both transmitting and receiving in some devices. -
Border 106 is not a physical border, but is shown to represent a space within which signals can be received from devices within the space. Thus, as one device transmits a signal representing a packet withinborder 106, other devices withinborder 106 pick up the signals and, as they are programmed, will attempt to determine if the signals represent packets and if so, then demodulate/decode the packets to obtain the transmitted data. - The algorithm adapted to detect the number of transmit antennas is described below with reference to a preamble with ELT symbols that are cyclically-shifted and transmitted from each of the transmit antennas of the MIMO system. In other words, the ELT symbols of the preamble are first transmitted from a first one of the transmit antennas and are thereafter cyclically-shifted the same number as the number of remaining transmit antennas of the MIMO system and subsequently transmitted from each such transmit antenna. It is understood, however, that the algorithm may also be applied to other training symbols.
- To detect the number of transmit antennas at the receiver, a fast Fourier transform (FFT) operation is performed on the received samples of the transmitted ELT symbols. Assume rq(n) represents the n-th received time-domain sample on the q-th receive antenna. Further assume that the FFT window of the training symbols includes Nc samples, and the first sample of this FFT window corresponds to n=0. Applying the FFT yields the following equation (1):
-
- where yq(i) represents the received information on receive antenna q and subcarrier i, and C1 is a normalization constant.
- Next, each subcarrier yq(i) is multiplied with the associated subcarrier frequency-domain representation of the ELT symbol so as to remove the effect of the ELT and to maintain the channel information. Assume xp(i) is the frequency-domain representation of the training symbol on subcarrier i and transmit antenna p (or spatial stream p). In the following, it is assumed that a direct mapping of Ns spatial streams to Nt transmit antennas occurs, therefore Ns=Nt, although it is understood that the present invention may be readily applied to more general space-time-frequency mappings where the Ns spatial streams are not directly mapped to the Nt transmit antennas. The training symbol is assumed to be a known reference to both the transmitter and receiver. Moreover, without loss of generality, it is assumed that no cyclic shift is applied to transmit
antenna 1. Accordingly, the received frequency-domain information is multiplied by the conjugate of x1(i) to obtain the following: -
y′ q(i)=y q(i)x 1*(i) (2) - where f(*) denotes the complex conjugation operation. Next, without loss of generality it is assumed that xp(i) utilizes all subcarriers. Hence, an inverse FFT (IFFT) can be performed to transform the frequency domain values of equation (2) into time domain values, as shown below:
-
- where C2 is a normalization constant.
- Neglecting contributions due to noise, equation (3) may be rewritten as shown below:
-
- where hf
— qp(n) is the time-domain representation of the communication channel between transmitter p and receiver q, in other words, the impulse response of the communication channel between transmitter p and receiver q, and sp denotes the cyclic shift in samples applied to the p-th transmit antenna. C3 is a normalization constant. - The above computations determine the degree of time-shift, if any, of the channel impulse response as detected by the receiver. In order to improve the accuracy of such a detection, cyclic window integration may be applied. Assume w(n) represents a window of Nw samples long. Accordingly, a cyclic window integration over the power of r′q(n), i.e., |r′q(n)|2, with n=0, 1, . . . Nc−1, yields the following:
-
- where mod is the modulo operator. It is understood that instead of using power of r′q(n) in the above equation, one may use, for example, the amplitude of r′q(n) or any other suitable measure. The maximum values meeting defined criteria in the intervals of expression (5) indicate the presence or absence of impulse responses in these intervals. The intervals are selected so as to match the various expected cyclic shifts of the ELT symbols.
- The following is an exemplary pseudo-code adapted to detect the number of transmit antennas of a MIMO system by determining the presence of maximum values in the various intervals associated with the cyclic integration windows, as defined in expression (5) above. The exemplary pseudo-code below assumes that the MIMO system includes no more than four transmit antennas. It is understood, however, that the following pseudo-code may be readily modified to detect the number of transmit antennas in a MIMO system having any number of transmit antennas. Assume that {M1, M2, . . . , M6} represent the maximum values in each of intervals {I1, I2, . . . , I6} as shown in
FIG. 4B for this example. Accordingly, the number of transmit antennas is detected as shown below: -
(1) {{if ((M2 > THR1) AND (M3 > THR1) AND (M4 > THR1)) Nt = 4 (2) elseif ((M5 > THR1) AND (M6 > THR1)) Nt = 3 (3) elseif (M3 > THR1) Nt = 2 (4) else Nt = 1 (5) if ((M2 > THR2) OR (M4 > THR2)) Nt = 4 (6) elseif ((M5 > THR2) OR (M6 > THR2)) Nt = 3 (7) if (mean(M2,M3,M4) > mean(M5,M6)) Nt = 4 (8) elseif (mean(M5,M6) > M3) Nt = 3 (9) if (max(M1,M2,M3,M4) < THR3*min(M1,M2,M3,M4)) Nt = 4 (10) elseif (max(M1,M5,M6) < THR3*min(M1,M5,M6)) Nt = 3 (11) elseif (max(M1,M3) < THR3*min(M1,M3)) Nt = 2 (12) else Nt = 1}} - In the above pseudo-code, parameters THR1, THR2 and THR3 represent adjustable threshold values that may vary with the noise power. An estimate of the noise power may be obtained by subtracting the received samples corresponding to two (or more) subsequent equivalent training symbols and calculating the power of the result.
- Lines 1-4 of the above pseudo-code, defining the first comparison rule, determine the maximum values that are above the designated threshold values(s) or noise floors. Lines 5-6, defining the second comparison rule, are used to verify whether certain peaks are above a higher threshold, thus ensuring that even if the peak (maximum) values are below the noise floor, the correct number of transmit antennas is detected. Lines 7-8 are used to distinguish between three TX and four TX case because for high delay spread cases in the event the first two comparison rules fail. Lines 9-12, defining the fourth comparison rule, are used to ensure that the highest and the lowest peak values are within a certain range (e.g., 15 or 20 dB). This is particularly important to distinguish between the one TX and two TX cases.
- Depending on the number of TX antennas, the result of the above computations contains a sum of time-shifted impulse responses.
FIG. 4A shows the result of such computations when Nt=2, Nc=64, s1=0 and s2=32. In other words, in the computations associated with data shown inFIG. 4A , the cyclic shift of the ELT symbol at the first TX antenna is 0 samples and that at the second TX antenna is 32 samples at a sampling rate of 20 MHz or, equivalently, 1.6 μs. When there are three transmit antennas, the shifts may be, e.g., 0, 21, and 42 samples; when there are four transmit antennas, the shifts may be, e.g., 0, 16, 32, and 48 samples, respectively, as understood by those skilled in the art. The absolute values of the complex numbers of the two TX channel impulse response is used in the plot ofFIG. 4B . - In accordance with equation (5), for a window of 4 samples, integrating the square powers of the values shown in
FIG. 4A results in the real parts as shown inFIG. 4B . Therefore, as described above, equation (5) may be used after equation (4) to improve the accuracy of the detection. For an interval size of 4 samples, the intervals for all possible shifts as mentioned in the exemplary pseudo code above are {I1, I2, I3, I4, I5, I6}={0-3, 16-19, 21-24, 32-35, 42-45, 48-51}, as shown inFIG. 4B . -
FIGS. 5A , 5B and 5C respectively show cyclically shifted preambles adapted for transmission from systems having respectively 2, 3 and 4 transmit antennas. As used herein, a sequence in the frequency domain is expressed with uppercase letters (e.g., L(i)), while the corresponding time sequence is expressed with lowercase letters (e.g., l(i)). - The preambles which enable or enhance coexistence of MIMO packets in legacy devices include a cyclic delay shift applied to the ELT as well as Signal field prior to applying the guard time extension. For example, assume L(i) and D(i) are the 64 subcarrier values for the ELT and Signal field symbols, respectively. For a conventional 802.11a single transmitter transmission, the time samples for the long training symbol are derived by taking the 64-point IFFT of L(i) to obtain l(n) and transmitting the samples of l(n). Thus, with the guard time, the ELT symbol and guard time are constructed as [l(32:63) l(0:63) l(0:63)], i.e., the IFFT output is repeated twice and the last 32 samples are prefixed to form the long training guard interval. As with the conventional timing, the long training guard interval (32 samples) is twice as long as the guard interval for 802.11a data symbols (16 samples). The signal field is formed by [d(48:63) d(0:63)], where d(0:63) are the 64 samples of the IFFT of D(i).
- In the case of an exemplary two transmitter MIMO device, the first transmitter transmits the long training symbol and signal field, as is the case with an of 802.11a transmission. The second transmitter, however, applies a cyclic shift such that instead of the IFFT output l(0:63), the cyclically shifted samples ls=[l(32:63) l(0:31)] are used to construct the long training symbol samples [ls(32:63) ls(0:63) ls(0:63)]. With respect to the signal field, the shifted samples ds=[d(32:63) d(0:31)] are used to construct the signal field as [ds(48:63) ds(0:63)].
- In a legacy 802.11a packet, one 3.2 microsecond repetition of the long training symbol L as shown in
FIG. 1 is expressed in the time domain as the IFFT of L(i), where L(i) contains 64 subcarrier values, of which 52 are non-zero. The time samples l(n) are given as shown in equation (6): -
- In accordance with the preambles adapted for detection of the number of transmit antennas as well as for extended modes operations, L(i) may contain more than 52 non-zero subcarriers. Furthermore, in the case of MIMO transmission, l(n) may have a cyclic shift that may be different for each transmitter. The shifted signal lk(n) can be derived from l(n) as lk(n)=l([n+64−sk]% 64), where “%” denotes the modulo operator and sk is the cyclic delay of transmitter k in 20 MHz samples. This expression assumes a 20 MHz sampling rate, such that there are 64 samples in a 3.2 microsecond interval. An alternative method of generating the cyclic shift is to apply a phase ramp rotation to all subcarrier values of L(i) prior to calculating the IFFT, such as that shown in equation (7) below:
-
- For a MIMO system with two transmit antennas and two different transmit data streams, cyclic delay values sk may be 0 and 32 samples, respectively, corresponding to a cyclic delay of 1.6 microseconds between the two transmitters. For three transmitters, sk may be 0, 21, and 42 samples, respectively. For four transmitters, sk may be 0, 16, 32, and 48 samples, respectively.
-
FIG. 6 shows aflowchart 600 of steps carried out to detect the number of transmit antennas. The process starts atstep 602. Atstep 604, the transmitted ELT symbols are received. Atstep 606 an FFT operation is performed on the received samples of the transmitted ELT symbols, possibly averaged over the two consecutive ELT symbols. Atstep 606 the FFT values are multiplied with known frequency-domain representation of the training symbols on each sub-carrier of the reference transmit antenna, herein assumed transmitantenna 1. Atstep 608, an inverse FFT or LS estimate is performed on the multiplied results to transform the frequency domain values of equation (2) into time domain values. Atstep 612, the number of shifted impulse responses in the channel impulse response are isolated to determine the number of transmit antennas. The process ends atstep 614. - The above embodiments of the present invention are illustrative and not limiting. Various alternatives and equivalents are possible. The invention is not limited by the type of encoding, decoding, modulation, demodulation, equalization, filtering, etc., performed. The invention is not limited to the number of transmit or receive antennas. The invention is not limited by the rate used to transfer the data. The invention is not limited by the type of integrated circuit in which the present disclosure may be disposed. Nor is the disclosure limited to any specific type of process technology, e.g., CMOS, Bipolar, or BICMOS that may be used to manufacture the present disclosure. Other additions, subtractions or modifications are obvious in view of the present disclosure and are intended to fall within the scope of the appended claims.
Claims (26)
y′ q(i)=y q(i)x 1*(i)
y′ q(i)=y q(i)x 1*(i)
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Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060182017A1 (en) * | 2005-02-16 | 2006-08-17 | Hansen Christopher J | Method and system for compromise greenfield preambles for 802.11n |
US20100061402A1 (en) * | 2003-04-10 | 2010-03-11 | Qualcomm Incorporated | Modified preamble structure for ieee 802.11a extensions to allow for coexistence and interoperability between 802.11a devices and higher data rate, mimo or otherwise extended devices |
US8457232B2 (en) * | 2004-05-27 | 2013-06-04 | Qualcomm Incorporated | Detecting the number of transmit antennas in wireless communication systems |
US8611457B2 (en) | 2003-04-10 | 2013-12-17 | Qualcomm Incorporated | Modified preamble structure for IEEE 802.11A extensions to allow for coexistence and interoperability between 802.11A devices and higher data rate, MIMO or otherwise extended devices |
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Families Citing this family (213)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8000223B2 (en) | 2004-04-12 | 2011-08-16 | Broadcom Corporation | Method and system for multi-antenna preambles for wireless networks preserving backward compatibility |
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US7660362B2 (en) * | 2004-06-18 | 2010-02-09 | Broadcom Corporation | Wireless local area network system using space-time block coding (STBC) having backward compatibility with prior standards |
US7643453B2 (en) * | 2004-06-22 | 2010-01-05 | Webster Mark A | Legacy compatible spatial multiplexing systems and methods |
US8077592B2 (en) | 2004-06-22 | 2011-12-13 | Intellectual Ventures I Llc | Packet processing systems and methods |
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US7646703B2 (en) | 2004-07-27 | 2010-01-12 | Broadcom Corporation | Backward-compatible long training sequences for wireless communication networks |
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US7826547B2 (en) * | 2004-10-26 | 2010-11-02 | Broadcom Corporation | Mixed mode preamble for MIMO wireless communications |
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US7826408B1 (en) | 2005-03-14 | 2010-11-02 | Ozmo, Inc. | Apparatus and method for integrating short-range wireless personal area networks for a wireless local area network infrastructure |
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US7558537B2 (en) * | 2005-06-07 | 2009-07-07 | Broadcom Corporation | Modified preamble for programmable transmitter |
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US7711061B2 (en) * | 2005-08-24 | 2010-05-04 | Broadcom Corporation | Preamble formats supporting high-throughput MIMO WLAN and auto-detection |
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US7944991B2 (en) * | 2005-10-27 | 2011-05-17 | Georgia Tech Research Corporation | Constrained clipping for peak-to-average power ratio (crest factor) reduction in multicarrier transmission systems |
US7813448B2 (en) * | 2005-10-31 | 2010-10-12 | Broadcom Corporation | Cyclic delay diversity in a wireless system |
US7489670B2 (en) * | 2005-12-27 | 2009-02-10 | Celeno Communications Ltd. | Device, system and method of uplink/downlink communication in wireless network |
US7656965B2 (en) | 2005-12-29 | 2010-02-02 | Celeno Communications (Israel) Ltd. | Method of secure WLAN communication |
US20070153754A1 (en) * | 2005-12-29 | 2007-07-05 | Nir Shapira | Method, apparatus and system of spatial division multiple access communication in a wireless local area network |
US7570624B2 (en) | 2005-12-29 | 2009-08-04 | Celeno Communications (Israel) Ltd. | Device, system and method of uplink/downlink communication in wireless network |
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US7672400B2 (en) | 2005-12-29 | 2010-03-02 | Celeno Communications (Israel) Ltd. | Method of secure WLAN communication |
US20070153760A1 (en) | 2005-12-29 | 2007-07-05 | Nir Shapira | Method, apparatus and system of spatial division multiple access communication in a wireless local area network |
US8891497B1 (en) * | 2006-03-14 | 2014-11-18 | Atmel Corporation | Method and apparatus for coordinating a wireless PAN network and a wireless LAN network |
US9130791B2 (en) | 2006-03-20 | 2015-09-08 | Qualcomm Incorporated | Uplink channel estimation using a signaling channel |
US7945214B2 (en) * | 2006-03-24 | 2011-05-17 | Lg Electronics Inc. | Method of reducing overhead for multi-input, multi-output transmission system |
US7742770B2 (en) | 2006-03-24 | 2010-06-22 | Agere Systems Inc. | Method and apparatus for improved antenna isolation for per-antenna training using variable scaling |
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US8494084B1 (en) | 2006-05-02 | 2013-07-23 | Marvell International Ltd. | Reuse of a matrix equalizer for the purpose of transmit beamforming in a wireless MIMO communication system |
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US20080101482A1 (en) * | 2006-10-26 | 2008-05-01 | General Instrument Corporation | Method and apparatus for refining MIMO channel estimation using the signal field of the data frame |
US8725142B1 (en) | 2006-10-31 | 2014-05-13 | Marvell International Ltd. | Channel scanning method and apparatus |
EP2122954A2 (en) * | 2007-01-15 | 2009-11-25 | Koninklijke Philips Electronics N.V. | Method of generating low peak-to-average power ratio ( papr) binary preamble sequences for ofdm systems |
US8259835B2 (en) | 2007-03-22 | 2012-09-04 | Marvell World Trade Ltd. | Variable codebook for MIMO system |
US8223872B1 (en) | 2007-04-04 | 2012-07-17 | Marvell International Ltd. | Reuse of a matrix equalizer for the purpose of transmit beamforming in a wireless MIMO communication system |
US8165543B2 (en) | 2007-04-25 | 2012-04-24 | Marvell World Trade Ltd. | Power amplifier adjustment for transmit beamforming in multi-antenna wireless systems |
US8199841B1 (en) | 2007-04-26 | 2012-06-12 | Marvell International Ltd. | Channel tracking in a wireless multiple-input multiple-output (MIMO) communication system |
US8130858B1 (en) | 2007-05-30 | 2012-03-06 | Marvell International Ltd. | Method and apparatus for implementing transmit diversity in OFDM systems |
CN101755391B (en) | 2007-07-18 | 2013-08-07 | 马维尔国际贸易有限公司 | Access point with simultaneous downlink transmission of independent data for multiple client stations |
US8149811B2 (en) | 2007-07-18 | 2012-04-03 | Marvell World Trade Ltd. | Wireless network with simultaneous uplink transmission of independent data from multiple client stations |
US8908667B1 (en) | 2007-09-07 | 2014-12-09 | Marvell International Ltd. | Method and apparatus for antenna path selection for multiple wireless communication components |
US9253742B1 (en) * | 2007-11-29 | 2016-02-02 | Qualcomm Incorporated | Fine timing for high throughput packets |
KR100914321B1 (en) * | 2007-12-03 | 2009-08-27 | 한국전자통신연구원 | Method for enbodying frame in wideband wireless communication system using multi antennas |
EP2223445B1 (en) * | 2007-12-10 | 2017-08-16 | Electronics and Telecommunications Research Institute | Network communication method and network device using preamble |
US8072959B2 (en) * | 2008-03-06 | 2011-12-06 | Issc Technologies Corp. | Generating method for short training field in IEEE 802.11n communication systems |
US8055230B1 (en) | 2008-03-25 | 2011-11-08 | Marvell International Ltd. | Low noise amplifier gain adaption based on a received signal strength indication of bluetooth and wlan signals |
JP4582193B2 (en) * | 2008-05-23 | 2010-11-17 | ソニー株式会社 | Receiving apparatus and receiving method |
GB2461684A (en) * | 2008-06-27 | 2010-01-13 | Vodafone Plc | Transmitting communication mode information between network elements |
US8982889B2 (en) | 2008-07-18 | 2015-03-17 | Marvell World Trade Ltd. | Preamble designs for sub-1GHz frequency bands |
US8351519B2 (en) * | 2008-08-15 | 2013-01-08 | Qualcomm Incorporated | Embedding information in an 802.11 signal field |
US20100046656A1 (en) * | 2008-08-20 | 2010-02-25 | Qualcomm Incorporated | Preamble extensions |
US20100290449A1 (en) | 2008-08-20 | 2010-11-18 | Qualcomm Incorporated | Preamble extensions |
US9252862B2 (en) * | 2008-09-17 | 2016-02-02 | Qualcomm Incorporated | MIMO preamble for initial access with an unknown number of transmit antennas |
US9590832B1 (en) | 2008-09-23 | 2017-03-07 | Marvell International Ltd. | Sub-carrier adaptation in multi-carrier communication systems |
CN101764627B (en) * | 2008-12-26 | 2014-05-07 | 株式会社Ntt都科摩 | Method for confirming demodulation pilot frequency sequence of uplink, terminal and uplink system |
WO2010081293A1 (en) | 2009-01-13 | 2010-07-22 | 华为技术有限公司 | Method, device and system for information transmitting and obtaining |
US8392781B2 (en) * | 2009-01-13 | 2013-03-05 | Texas Instruments Incorporated | Hybrid-ARQ (HARQ) with scrambler |
US8335167B1 (en) | 2009-02-02 | 2012-12-18 | Marvell International Ltd. | Refining beamforming techniques for phased-array antennas |
WO2010099040A1 (en) | 2009-02-24 | 2010-09-02 | Marvell World Trade Ltd. | Techniques for flexible and efficient beamforming |
US9924512B1 (en) | 2009-03-24 | 2018-03-20 | Marvell International Ltd. | OFDMA with block tone assignment for WLAN |
WO2010120692A1 (en) * | 2009-04-13 | 2010-10-21 | Marvell World Trade Ltd. | Physical layer frame format for wlan |
US8599803B1 (en) | 2009-05-01 | 2013-12-03 | Marvell International Ltd. | Open loop multiple access for WLAN |
US8437440B1 (en) | 2009-05-28 | 2013-05-07 | Marvell International Ltd. | PHY frame formats in a system with more than four space-time streams |
US20100311432A1 (en) * | 2009-06-05 | 2010-12-09 | Broadcom Corporation | Cluster parsing for signaling within multiple user, multiple access, and/or mimo wireless communications |
US8385443B2 (en) * | 2009-07-17 | 2013-02-26 | Qualcomm Incorporated | Constructing very high throughput long training field sequences |
US8917784B2 (en) * | 2009-07-17 | 2014-12-23 | Qualcomm Incorporated | Method and apparatus for constructing very high throughput long training field sequences |
US8571010B1 (en) | 2009-07-21 | 2013-10-29 | Marvell International Ltd. | Simultaneous uplink transmission in a wireless network |
US9077594B2 (en) | 2009-07-23 | 2015-07-07 | Marvell International Ltd. | Coexistence of a normal-rate physical layer and a low-rate physical layer in a wireless network |
US9706599B1 (en) | 2009-07-23 | 2017-07-11 | Marvell International Ltd. | Long wireless local area network (WLAN) packets with midambles |
US9596715B1 (en) | 2009-07-23 | 2017-03-14 | Marvell International Ltd. | Long wireless local area network (WLAN) packets with midambles |
EP3182629B1 (en) | 2009-07-29 | 2019-09-04 | Marvell World Trade Ltd. | Methods and apparatus for wlan transmission |
US20110038441A1 (en) * | 2009-08-12 | 2011-02-17 | Cambridge Silicon Radio Limited | Transmission mode detection |
US9503931B2 (en) * | 2009-08-12 | 2016-11-22 | Qualcomm Incorporated | Enhancements to the MU-MIMO VHT preamble to enable mode detection |
US8472381B1 (en) | 2009-08-14 | 2013-06-25 | Marvell International Ltd. | Methods and apparatus for antenna spoofing |
US8660497B1 (en) | 2009-08-18 | 2014-02-25 | Marvell International Ltd. | Beamsteering in a spatial division multiple access (SDMA) system |
CN105681000A (en) | 2009-08-21 | 2016-06-15 | 应用转换有限责任公司 | OFDM communication method and transmitter used for OFDM communication |
US8665949B1 (en) | 2009-09-09 | 2014-03-04 | Marvell International Ltd. | Methods and apparatus for transmission of data at different modulation and/or coding rates |
KR101335733B1 (en) * | 2009-09-29 | 2013-12-02 | 후지쯔 가부시끼가이샤 | Method and device for adding pilot |
WO2011050320A1 (en) * | 2009-10-23 | 2011-04-28 | Marvell World Trade Ltd. | Number of streams indication for wlan |
US9480018B2 (en) | 2009-11-03 | 2016-10-25 | Marvell World Trade Ltd. | Phy data unit format for MIMO |
US8472383B1 (en) | 2009-11-24 | 2013-06-25 | Marvell International Ltd. | Group management in multiuser communications |
US8886755B1 (en) | 2009-12-09 | 2014-11-11 | Marvell International Ltd. | Method and apparatus for facilitating simultaneous transmission from multiple stations |
KR20110082685A (en) * | 2010-01-12 | 2011-07-20 | 삼성전자주식회사 | Method for generating preamble in multi-user multi-input multi-output system, data transmission device and user terminal of enabling the method |
US9031122B2 (en) * | 2010-01-29 | 2015-05-12 | Qualcomm Incorporated | Reducing phase errors on a communication device |
US8971178B1 (en) | 2010-04-05 | 2015-03-03 | Marvell International Ltd. | Calibration correction for implicit beamformer using an explicit beamforming technique in a wireless MIMO communication system |
US9444577B1 (en) | 2010-04-05 | 2016-09-13 | Marvell International Ltd. | Calibration correction for implicit beamformer using an explicit beamforming technique in a wireless MIMO communication system |
US9397785B1 (en) | 2010-04-12 | 2016-07-19 | Marvell International Ltd. | Error detection in a signal field of a WLAN frame header |
US8665908B1 (en) | 2010-05-11 | 2014-03-04 | Marvell International Ltd. | Signaling guard interval capability in a communication system |
EP2583385B1 (en) | 2010-06-16 | 2018-04-18 | Marvell World Trade Ltd. | Alternate feedback types for downlink multiple user mimo configurations |
US9021341B1 (en) | 2010-06-16 | 2015-04-28 | Marvell International Ltd. | LDPC coding in a communication system |
US9001908B2 (en) | 2010-07-01 | 2015-04-07 | Marvell World Trade Ltd. | Orthogonal frequency division multiplexing (OFDM) symbol formats for a wireless local area network (WLAN) |
US9025681B2 (en) | 2010-07-01 | 2015-05-05 | Marvell World Trade Ltd. | Modulation of signal field in a WLAN frame header |
WO2012021449A1 (en) | 2010-08-10 | 2012-02-16 | Marvell World Trade Ltd. | Sub-band feedback for beamforming on downlink multiple user mimo configurations |
US8891597B1 (en) | 2010-08-17 | 2014-11-18 | Marvell International Ltd. | Calibration for implicit transmit beamforming |
US9531498B2 (en) | 2010-09-01 | 2016-12-27 | Marvell World Trade Ltd. | Link adaptation in a communication network |
US9178651B2 (en) | 2010-09-29 | 2015-11-03 | Marvell World Trade Ltd. | Stream parsing in a communication system |
WO2012047855A2 (en) | 2010-10-04 | 2012-04-12 | Marvell World Trade Ltd. | Compressed feedback format for wlan |
KR101923201B1 (en) | 2010-10-07 | 2019-02-27 | 마벨 월드 트레이드 리미티드 | Tone reordering in a wireless communication system |
US9300511B2 (en) | 2011-01-05 | 2016-03-29 | Qualcomm Incorporated | Method and apparatus for improving throughput of 5 MHZ WLAN transmissions |
EP2668736B1 (en) | 2011-01-28 | 2018-04-25 | Marvell World Trade Ltd. | Physical layer frame format for long range wlan |
EP3327965B1 (en) | 2011-02-04 | 2019-09-25 | Marvell World Trade Ltd. | Control mode phy for wlan |
US9674317B2 (en) | 2011-02-10 | 2017-06-06 | Marvell World Trade Ltd. | Multi-clock PHY preamble design and detection |
WO2012145404A2 (en) | 2011-04-18 | 2012-10-26 | Marvell World Trade Ltd. | Reducing power consumption in an wireless communication system |
US9385848B2 (en) | 2011-05-20 | 2016-07-05 | Microsoft Technology Licensing, Llc | Short-range nodes with adaptive preambles for coexistence |
US9401832B2 (en) | 2011-05-20 | 2016-07-26 | Microsoft Technology Licensing, Llc | Long-range nodes with adaptive preambles for coexistence |
EP2715965B1 (en) | 2011-05-26 | 2017-10-18 | Marvell World Trade Ltd. | Sounding packet format for long range wlan |
US9019914B2 (en) | 2011-06-08 | 2015-04-28 | Marvell World Trade Ltd. | Efficient transmission for low data rate WLAN |
JP6053197B2 (en) | 2011-07-15 | 2016-12-27 | マーベル ワールド トレード リミテッド | Coexistence in normal and low rate physical layer wireless networks |
EP2745554B1 (en) | 2011-08-18 | 2018-10-10 | Marvell World Trade Ltd. | Signal field design for wlan |
CN103765973B (en) | 2011-08-29 | 2017-11-10 | 马维尔国际贸易有限公司 | Normal speed physical layer and low rate physical layer coexisting in the wireless network |
US9398615B1 (en) | 2011-09-07 | 2016-07-19 | Marvell International Ltd. | Carrier sensing and symbol timing in a WLAN system |
US9154969B1 (en) | 2011-09-29 | 2015-10-06 | Marvell International Ltd. | Wireless device calibration for implicit transmit |
WO2013063207A1 (en) | 2011-10-28 | 2013-05-02 | Corning Incorporated | Glass articles with infrared reflectivity and methods for making the same |
CN104115541B (en) | 2011-11-02 | 2018-01-12 | 马维尔国际贸易有限公司 | Method for wireless communications and equipment |
JP6124362B2 (en) * | 2011-11-02 | 2017-05-10 | マーベル ワールド トレード リミテッド | Method and apparatus for automatically detecting the physical layer (PHY) mode of a data unit in a wireless local area network (WLAN) |
US9155027B1 (en) | 2011-11-23 | 2015-10-06 | Marvell International Ltd. | 802.11 enhanced distributed channel access |
US9351333B1 (en) | 2011-11-30 | 2016-05-24 | Marvell International Ltd. | Long wireless local area network (WLAN) packets with midambles |
US8923432B2 (en) * | 2011-12-02 | 2014-12-30 | Qualcomm Incorporated | Systems and methods for communication over a plurality of frequencies and streams |
JP5259809B2 (en) * | 2011-12-05 | 2013-08-07 | 株式会社東芝 | Transmitter, receiver and method in a multi-antenna wireless communication system |
US9019991B1 (en) | 2011-12-08 | 2015-04-28 | Marvell International Ltd. | Method and apparatus for detecting a packet in a WLAN system |
WO2013104999A2 (en) | 2012-01-13 | 2013-07-18 | Marvell World Trade Ltd. | Data unit format for single user beamforming in long-range wireless local area networks (wlans) |
KR20200024960A (en) | 2012-02-07 | 2020-03-09 | 마벨 월드 트레이드 리미티드 | Pilot sequence design for long range wlan |
CN104247316B (en) | 2012-04-03 | 2018-10-02 | 马维尔国际贸易有限公司 | Physical layer frame format for WLAN |
US9735855B2 (en) | 2012-04-18 | 2017-08-15 | Marvell World Trade Ltd. | Method and apparatus for relaying communication between an access point and a station in a wireless network |
US9445349B1 (en) | 2012-04-18 | 2016-09-13 | Marvell International Ltd. | 802.11ah duty cycle based channel access priorities |
US9386516B2 (en) | 2012-06-29 | 2016-07-05 | Marvell World Trade Ltd. | Using duration field in beacon to reserve channel time subsequent to beacon |
WO2014022693A1 (en) | 2012-08-03 | 2014-02-06 | Marvell World Trade Ltd. | Multi-mode indication subfield in a signal field of a wireless local area network data unit |
WO2014039616A1 (en) | 2012-09-06 | 2014-03-13 | Marvell World Trade Ltd. | Efficient search of precoders in precoded mimo systems |
WO2014169110A1 (en) | 2013-04-10 | 2014-10-16 | Marvell World Trade Ltd. | Method and apparatus of mitigating interference in a wireless network though use of transmit beamforming |
US10320459B2 (en) | 2013-04-10 | 2019-06-11 | Marvell World Trade Ltd. | Method and apparatus for mitigating interference in a wireless network through use of transmit beamforming |
WO2014183059A1 (en) | 2013-05-10 | 2014-11-13 | Marvell World Trade Ltd. | Physical layer frame format for wlan |
WO2014205743A1 (en) * | 2013-06-27 | 2014-12-31 | 华为技术有限公司 | Long training sequence generating method, and signal sending method and apparatus |
US9843097B1 (en) | 2013-07-08 | 2017-12-12 | Marvell International Ltd. | MIMO implicit beamforming techniques |
US9071474B1 (en) | 2013-07-25 | 2015-06-30 | Marvell International Ltd. | Systems and methods for suppressing interference in a wireless communication system |
US9648620B2 (en) | 2013-08-28 | 2017-05-09 | Qualcomm Incorporated | Tone allocation for multiple access wireless networks |
CN105659552B (en) | 2013-09-10 | 2019-09-13 | 马维尔国际贸易有限公司 | For generating the method and apparatus for having the data cell of selectable protection interval |
US9629169B2 (en) | 2013-09-16 | 2017-04-18 | Marvell World Trade Ltd. | Access point coordination for traffic control in wireless networks |
US10194006B2 (en) | 2013-10-25 | 2019-01-29 | Marvell World Trade Ltd. | Physical layer frame format for WLAN |
US10218822B2 (en) | 2013-10-25 | 2019-02-26 | Marvell World Trade Ltd. | Physical layer frame format for WLAN |
EP3061219B1 (en) | 2013-10-25 | 2020-04-08 | Marvell World Trade Ltd. | Range extension mode for wifi |
US10257806B2 (en) | 2013-11-11 | 2019-04-09 | Marvell World Trade Ltd. | Medium access control for multi-channel OFDM in a wireless local area network |
US9825678B2 (en) | 2013-11-26 | 2017-11-21 | Marvell World Trade Ltd. | Uplink multi-user multiple input multiple output for wireless local area network |
WO2015081288A1 (en) | 2013-11-27 | 2015-06-04 | Marvell Semiconductor, Inc. | Medium access protection and bandwidth negotiation in a wireless local area network |
US9473341B2 (en) | 2013-11-27 | 2016-10-18 | Marvell World Trade Ltd. | Sounding and tone block allocation for orthogonal frequency multiple access (OFDMA) in wireless local area networks |
CN105981341B (en) | 2013-11-27 | 2020-11-13 | 马维尔亚洲私人有限公司 | Communication method and communication device for orthogonal frequency division multiple access of wireless local area network |
US9166660B2 (en) | 2013-11-27 | 2015-10-20 | Marvell World Trade Ltd. | Uplink multi-user multiple input multiple output beamforming |
US20150173118A1 (en) * | 2013-12-18 | 2015-06-18 | Qualcomm Incorporated | Flexible extended signaling |
US9935794B1 (en) | 2014-03-24 | 2018-04-03 | Marvell International Ltd. | Carrier frequency offset estimation |
CN106416165B (en) | 2014-04-16 | 2019-08-13 | 马维尔国际贸易有限公司 | For generating and handling the method for physical layer data units and for the device of communication |
US11855818B1 (en) | 2014-04-30 | 2023-12-26 | Marvell Asia Pte Ltd | Adaptive orthogonal frequency division multiplexing (OFDM) numerology in a wireless communication network |
EP3138254A1 (en) * | 2014-05-01 | 2017-03-08 | Marvell World Trade Ltd. | Multi-clock phy preamble design and detection |
CN107078870B (en) | 2014-05-02 | 2021-01-26 | 马维尔国际有限公司 | Multi-user allocation signaling in a wireless communication network |
US9596060B1 (en) | 2014-05-09 | 2017-03-14 | Marvell International Ltd. | Tone block allocation for orthogonal frequency division multiple access data unit |
US10164695B2 (en) | 2014-05-09 | 2018-12-25 | Marvell World Trade Ltd. | Tone block and spatial stream allocation |
KR20170013905A (en) * | 2014-06-02 | 2017-02-07 | 마벨 월드 트레이드 리미티드 | High efficiency orthogonal frequency division multiplexing (ofdm) physical layer (phy) |
EP3155778B1 (en) | 2014-06-11 | 2019-02-20 | Marvell World Trade Ltd. | Compressed ofdm symbols in a wireless communication system |
WO2016014969A1 (en) | 2014-07-24 | 2016-01-28 | Marvell Semiconductor, Inc. | Group acknowledgement for multiple user communication in a wireless local area network |
KR102305631B1 (en) * | 2014-08-21 | 2021-09-28 | 엘지전자 주식회사 | Method for transmitting preamble in wireless lan system |
CN105580302B (en) * | 2014-08-30 | 2019-04-19 | 华为技术有限公司 | A kind of method, channel estimation methods and device sending data |
US10075226B2 (en) * | 2014-10-03 | 2018-09-11 | Qualcomm Incorporated | Per stream and per antenna cyclic shift delay in uplink multi-user MIMO |
US9804918B1 (en) | 2014-10-10 | 2017-10-31 | Marvell International Ltd. | Method and apparatus for generating a PHY data unit |
WO2016089998A1 (en) | 2014-12-02 | 2016-06-09 | Marvell Semiconductor, Inc. | Signal fields in a high efficiency wireless local area network (hew) data unit |
US10390328B2 (en) | 2014-12-05 | 2019-08-20 | Marvell World Trade Ltd. | Beamforming training in orthogonal frequency division multiple access (OFDMA) communication systems |
CN107431584B (en) | 2014-12-05 | 2020-11-03 | 马维尔国际有限公司 | Method and apparatus for communicating in a wireless communication network |
CN107409113A (en) | 2015-01-08 | 2017-11-28 | 马维尔国际贸易有限公司 | Efficient WLAN(WLAN)In downlink signaling |
US10306603B1 (en) | 2015-02-09 | 2019-05-28 | Marvell International Ltd. | Resource request for uplink multi-user transmission |
US9826532B1 (en) | 2015-02-09 | 2017-11-21 | Marvell International Ltd. | Orthogonal frequency division multiple access resource request |
US9674011B1 (en) | 2015-02-10 | 2017-06-06 | Marvel International Ltd. | Auto-detection of repeated signals |
CN109314991B (en) | 2015-04-09 | 2022-08-05 | 恩智浦美国有限公司 | Contention-based Orthogonal Frequency Division Multiple Access (OFDMA) communications |
US10153857B1 (en) | 2015-04-10 | 2018-12-11 | Marvell International Ltd. | Orthogonal frequency division multiple access protection |
WO2016176096A1 (en) | 2015-04-30 | 2016-11-03 | Corning Incorporated | Electrically conductive articles with discrete metallic silver layers and methods for making same |
US10181966B1 (en) | 2015-05-01 | 2019-01-15 | Marvell International Ltd. | WiFi classification by pilot sequences |
US10382598B1 (en) | 2015-05-01 | 2019-08-13 | Marvell International Ltd. | Physical layer frame format for WLAN |
US9949259B2 (en) * | 2015-05-07 | 2018-04-17 | Qualcomm Incorporated | System and method for transmitting data payload in WB SC, aggregate SC, duplicate SC, OFDM transmission frames |
CN113411111A (en) | 2015-06-08 | 2021-09-17 | 马维尔亚洲私人有限公司 | Explicit beamforming in efficient wireless local area networks |
WO2016201132A1 (en) | 2015-06-09 | 2016-12-15 | Marvell Semiconductor, Inc. | Channel access for simultaneous uplink transmissons by multiple communication devices |
US10038518B1 (en) | 2015-06-11 | 2018-07-31 | Marvell International Ltd. | Signaling phy preamble formats |
US10492221B1 (en) | 2015-06-25 | 2019-11-26 | Marvell International Ltd. | Methods and apparatus for protecting transmissions in a wireless communication network |
US10201009B1 (en) | 2015-08-13 | 2019-02-05 | Marvell International Ltd. | Methods and apparatus for protecting transmissions in a wireless communication network |
US10136435B1 (en) | 2015-08-13 | 2018-11-20 | Marvell International Ltd. | Orthogonal frequency division multiplex data unit decoding |
US10079709B2 (en) | 2015-08-14 | 2018-09-18 | Marvell World Trade Ltd. | Physical layer data unit format for a wireless communication network |
US11082888B2 (en) | 2015-10-20 | 2021-08-03 | Nxp Usa, Inc. | Single acknowledgment policy for aggregate MPDU |
WO2017070393A1 (en) | 2015-10-20 | 2017-04-27 | Marvell World Trade Ltd. | Acknowledgment data unit for multiple uplink data units |
US10742285B1 (en) | 2015-11-13 | 2020-08-11 | Marvell International Ltd. | Explicit multiuser beamforming training in a wireless local area network |
WO2017100741A1 (en) * | 2015-12-11 | 2017-06-15 | Marvell World Trade Ltd. | Signal field encoding in a high efficiency wireless local area network (wlan) data unit |
WO2017106516A1 (en) | 2015-12-15 | 2017-06-22 | Marvell Semiconductor, Inc. | Triggered uplink transmissions in wireless local area networks |
US10313923B2 (en) | 2016-02-19 | 2019-06-04 | Marvell World Trade Ltd. | Acknowledgement of transmissions in a wireless local area network |
EP3417557A1 (en) | 2016-02-19 | 2018-12-26 | Marvell World Trade, Ltd. | Acknowledgement of transmissions in a wireless local area network |
US10873878B2 (en) | 2016-02-19 | 2020-12-22 | Nxp Usa, Inc. | Acknowledgement of transmissions in a wireless local area network |
WO2017151932A1 (en) | 2016-03-02 | 2017-09-08 | Marvell Semiconductor, Inc. | Multiple traffic class data aggregation in a wireless local area network |
CN109479275B (en) | 2016-04-12 | 2023-07-04 | 恩智浦美国有限公司 | Uplink multi-user transmission |
CN109478966A (en) | 2016-04-14 | 2019-03-15 | 马维尔国际贸易有限公司 | Determine the channel availability for orthogonal frequency division multiple access operation |
WO2018222226A1 (en) * | 2017-02-16 | 2018-12-06 | Arizona Board Of Regents On Behalf Of The University Of Arizona | A method for exploiting preamble waveforms to support device and network functionalities in wireless systems |
EP3635926B1 (en) | 2017-06-09 | 2024-03-27 | Marvell World Trade Ltd. | Packets with midambles having compressed ofdm symbols |
US10715365B2 (en) | 2017-09-22 | 2020-07-14 | Nxp Usa, Inc. | Determining number of midambles in a packet |
US11477807B2 (en) * | 2017-12-29 | 2022-10-18 | Intel Corporation | Enhanced signal detection for wireless communications |
US10904059B2 (en) * | 2018-11-02 | 2021-01-26 | Qualcomm Incorporated | Control channel for vehicle-to-everything (V2X) communication |
US11095391B2 (en) | 2018-12-19 | 2021-08-17 | Nxp Usa, Inc. | Secure WiFi communication |
JP2022525555A (en) | 2019-03-21 | 2022-05-17 | マーベル アジア ピーティーイー、リミテッド | Coordinated multi-user transmission with multiple access points |
CN111628833B (en) * | 2020-06-10 | 2022-02-08 | 桂林电子科技大学 | MIMO antenna number estimation method based on convolutional neural network |
CN113556157B (en) * | 2021-06-08 | 2022-11-08 | 西安电子科技大学 | Method and system for estimating number of transmitting antennas of MIMO system under non-Gaussian interference |
Citations (93)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5131006A (en) * | 1990-09-06 | 1992-07-14 | Ncr Corporation | Carrier detection for a wireless local area network |
US5553064A (en) * | 1994-04-05 | 1996-09-03 | Stanford Telecommunications, Inc. | High speed bidirectional digital cable transmission system |
US5694421A (en) * | 1995-03-17 | 1997-12-02 | Samsung Electronics Co., Ltd. | Frequency-selective interference signal detecting apparatus and method thereof |
US6055231A (en) * | 1997-03-12 | 2000-04-25 | Interdigital Technology Corporation | Continuously adjusted-bandwidth discrete-time phase-locked loop |
US6118806A (en) * | 1998-05-29 | 2000-09-12 | Kdd Corporation | Signal synthesis method and apparatus under diversity reception |
US6144711A (en) * | 1996-08-29 | 2000-11-07 | Cisco Systems, Inc. | Spatio-temporal processing for communication |
US6226508B1 (en) * | 1997-07-04 | 2001-05-01 | Matsushita Electric Industrial Co., Ltd. | Transmission diversity apparatus |
US6260167B1 (en) * | 1999-02-23 | 2001-07-10 | Advanced Micro Devices, Inc. | Apparatus and method for deterministic receiver testing |
US6304750B1 (en) * | 1998-11-06 | 2001-10-16 | Lucent Technologies Inc. | Space-time diversity receiver for wireless systems |
US20010033603A1 (en) * | 2000-01-21 | 2001-10-25 | Microgistics, Inc. | Spread spectrum burst signal receiver and related methods |
US20020012411A1 (en) * | 2000-04-05 | 2002-01-31 | Johann Heinzl | Global positioning system receiver capable of functioning in the presence of interference |
US20020065047A1 (en) * | 2000-11-30 | 2002-05-30 | Moose Paul H. | Synchronization, channel estimation and pilot tone tracking system |
US20020101825A1 (en) * | 2001-01-30 | 2002-08-01 | Beck Eric C. | Optimal channel sounding system |
US20020111142A1 (en) * | 2000-12-18 | 2002-08-15 | Klimovitch Gleb V. | System, apparatus, and method of estimating multiple-input multiple-output wireless channel with compensation for phase noise and frequency offset |
US20020118635A1 (en) * | 2000-11-13 | 2002-08-29 | Nee Didier Johannes R. Van | Communication system |
US20020122511A1 (en) * | 2000-09-01 | 2002-09-05 | Alan Kwentus | Satellite receiver |
US6473467B1 (en) * | 2000-03-22 | 2002-10-29 | Qualcomm Incorporated | Method and apparatus for measuring reporting channel state information in a high efficiency, high performance communications system |
US20020160737A1 (en) * | 2001-03-06 | 2002-10-31 | Magis Networks, Inc. | Method and apparatus for diversity antenna branch selection |
US20020163933A1 (en) * | 2000-11-03 | 2002-11-07 | Mathilde Benveniste | Tiered contention multiple access (TCMA): a method for priority-based shared channel access |
US20030012160A1 (en) * | 2001-07-06 | 2003-01-16 | Webster Mark A. | Wireless communication system configured to communicate using a mixed waveform configuration |
US20030072255A1 (en) * | 2001-10-17 | 2003-04-17 | Jianglei Ma | System access and synchronization methods for MIMO OFDM communications systems and physical layer packet and preamble design |
US6563460B2 (en) * | 1999-01-08 | 2003-05-13 | Trueposition, Inc. | Collision recovery in a wireless location system |
US20030153275A1 (en) * | 2002-02-14 | 2003-08-14 | Interdigital Technology Corporation | Wireless communication system having adaptive threshold for timing deviation measurement and method |
US20030210646A1 (en) * | 2002-05-10 | 2003-11-13 | Kddi Corporation | Frequency error correction device and OFDM receiver with the device |
US6661857B1 (en) * | 2000-07-10 | 2003-12-09 | Intersil Americas Inc. | Rapid estimation of wireless channel impulse response |
US20030236108A1 (en) * | 2000-11-15 | 2003-12-25 | Jiang Li | Spatial domain matched filtering method and array receiver in wireless communication system |
US6670310B2 (en) * | 2000-12-12 | 2003-12-30 | Cleveland Punch And Die Co | High performance lubricant for metal punching and shearing |
US20040001430A1 (en) * | 2002-04-18 | 2004-01-01 | Gardner Steven H. | Method and apparatus for preamble detection and time synchronization estimation in OFDM communication systems |
US20040005022A1 (en) * | 2002-07-03 | 2004-01-08 | Oki Techno Centre (Singapore) Pte Ltd. | Receiver and method for WLAN burst type signals |
US20040005018A1 (en) * | 2002-07-03 | 2004-01-08 | Oki Techno Centre (Singapore) Pte Ltd | Receiver and method for WLAN burst type signals |
US6690715B2 (en) * | 1999-06-29 | 2004-02-10 | Intersil Americas Inc. | Rake receiver with embedded decision feedback equalizer |
US20040030530A1 (en) * | 2002-01-30 | 2004-02-12 | Kuo-Hui Li | Apparatus and method for detection of direct sequence spread spectrum signals in networking systems |
US20040032825A1 (en) * | 2002-08-19 | 2004-02-19 | Halford Steven D. | Wireless receiver for sorting packets |
US20040048574A1 (en) * | 2001-09-26 | 2004-03-11 | General Atomics | Method and apparatus for adapting multi-band ultra-wideband signaling to interference sources |
US20040052231A1 (en) * | 2002-03-18 | 2004-03-18 | Kumar Ramaswamy | Method and apparatus for indicating the presence of a wireless local area network by detecting signature sequences |
US20040071104A1 (en) * | 2002-07-03 | 2004-04-15 | Commasic, Inc. | Multi-mode method and apparatus for performing digital modulation and demodulation |
US20040100939A1 (en) * | 2002-11-26 | 2004-05-27 | Kriedte Kai Roland | Symbol timing for MIMO OFDM and other wireless communication systems |
US20040116112A1 (en) * | 2001-03-08 | 2004-06-17 | Gray Steven D. | Apparatus, and associated method, for reporting a measurement summary in a radio communication system |
US20040114546A1 (en) * | 2002-09-17 | 2004-06-17 | Nambirajan Seshadri | System and method for providing a mesh network using a plurality of wireless access points (WAPs) |
US20040120428A1 (en) * | 2002-12-18 | 2004-06-24 | Maltsev Alexander A. | Adaptive channel estimation for orthogonal frequency division multiplexing systems or the like |
US6757322B2 (en) * | 1998-11-24 | 2004-06-29 | Linex Technologies, Inc. | Space diversity and coding, spread-spectrum antenna and method |
US20040161046A1 (en) * | 2002-12-23 | 2004-08-19 | International Business Machines Corporation | Acquisition and adjustment of gain, receiver clock frequency, and symbol timing in an OFDM radio receiver |
US20040190560A1 (en) * | 2003-03-28 | 2004-09-30 | Maltsev Alexander A. | Receiver and method to detect and synchronize with a symbol boundary of an OFDM symbol |
US20040198265A1 (en) * | 2002-12-31 | 2004-10-07 | Wallace Bradley A. | Method and apparatus for signal decoding in a diversity reception system with maximum ratio combining |
US20040204026A1 (en) * | 2003-04-09 | 2004-10-14 | Ar Card | Method, apparatus and system of configuring a wireless device based on location |
US20040242273A1 (en) * | 2003-05-30 | 2004-12-02 | Corbett Christopher J. | Using directional antennas to enhance throughput in wireless networks |
US20040240402A1 (en) * | 2003-05-27 | 2004-12-02 | Stephens Adrian P. | Multiple mode support in a wireless local area network |
US20040258025A1 (en) * | 2003-06-18 | 2004-12-23 | University Of Florida | Wireless lan compatible multi-input multi-output system |
US20040266375A1 (en) * | 2003-06-27 | 2004-12-30 | Qinghua Li | Switching schemes for multiple antennas |
US20050002327A1 (en) * | 2003-04-07 | 2005-01-06 | Shaolin Li | Single chip multi-antenna wireless data processor |
US20050018754A1 (en) * | 1999-03-15 | 2005-01-27 | Lg Electronics Inc. | Pilot signals for synchronization and/or channel estimation |
US20050030886A1 (en) * | 2003-08-07 | 2005-02-10 | Shiquan Wu | OFDM system and method employing OFDM symbols with known or information-containing prefixes |
US20050047384A1 (en) * | 2003-08-27 | 2005-03-03 | Wavion Ltd. | WLAN capacity enhancement using SDM |
US20050105460A1 (en) * | 2003-11-19 | 2005-05-19 | Samsung Electronics Co., Ltd. | Apparatus and method for generating a preamble sequence in an orthogonal frequency division multiplexing communication system |
US20050152314A1 (en) * | 2003-11-04 | 2005-07-14 | Qinfang Sun | Multiple-input multiple output system and method |
US20050180353A1 (en) * | 2004-02-13 | 2005-08-18 | Hansen Christopher J. | MIMO wireless communication greenfield preamble formats |
US6934323B2 (en) * | 2000-07-10 | 2005-08-23 | Mitsubishi Denki Kabushiki Kaisha | Adaptive array antenna-based CDMA receiver that can find the weight vectors with a reduced amount of calculations |
US20050233709A1 (en) * | 2003-04-10 | 2005-10-20 | Airgo Networks, Inc. | Modified preamble structure for IEEE 802.11a extensions to allow for coexistence and interoperability between 802.11a devices and higher data rate, MIMO or otherwise extended devices |
US20050237992A1 (en) * | 2004-04-15 | 2005-10-27 | Airgo Networks, Inc. | Packet concatenation in wireless networks |
US20050281241A1 (en) * | 2004-06-22 | 2005-12-22 | Webster Mark A | Legacy compatible spatial multiplexing systems and methods |
US20060013327A1 (en) * | 2002-03-01 | 2006-01-19 | Ipr Licensing, Inc. | Apparatus for antenna diversity using joint maximal ratio combining |
US20060034389A1 (en) * | 2004-08-12 | 2006-02-16 | Tsuguhide Aoki | Wireless transmitting device and method |
US7006040B2 (en) * | 2000-12-21 | 2006-02-28 | Hitachi America, Ltd. | Steerable antenna and receiver interface for terrestrial broadcast |
US20060088120A1 (en) * | 2004-10-26 | 2006-04-27 | Hansen Christopher J | Mixed mode preamble for MIMO wireless communications |
US7082159B2 (en) * | 2000-11-29 | 2006-07-25 | Telefonaktiebolaget Lm Ericsson (Publ) | Methods and arrangements in a telecommunications system |
US7088782B2 (en) * | 2001-04-24 | 2006-08-08 | Georgia Tech Research Corporation | Time and frequency synchronization in multi-input, multi-output (MIMO) systems |
US7106709B2 (en) * | 2000-11-29 | 2006-09-12 | Telefonaktiebologet Lm Ericsson (Publ) | Timing drift compensation in wireless packet-based systems |
US7106784B2 (en) * | 2002-01-25 | 2006-09-12 | Sasken Communication Technologies Limited | Universal rake receiver |
US7123662B2 (en) * | 2001-08-15 | 2006-10-17 | Mediatek Inc. | OFDM detection apparatus and method for networking devices |
US20060270364A1 (en) * | 2005-05-31 | 2006-11-30 | Tsuguhide Aoki | Wireless packet transmitting device and method using a plurality of antennas |
US20060281487A1 (en) * | 2005-06-09 | 2006-12-14 | Girardeau James W Jr | Increased data rate transmissions of a wireless communication |
US7161996B1 (en) * | 2002-02-05 | 2007-01-09 | Airgo Networks, Inc. | Multi-antenna wireless receiver chains with vector decoding |
US7177369B2 (en) * | 2001-04-27 | 2007-02-13 | Vivato, Inc. | Multipath communication methods and apparatuses |
US7184495B2 (en) * | 2001-09-24 | 2007-02-27 | Atheros Communications, Inc. | Efficient pilot tracking method for OFDM receivers |
US7190748B2 (en) * | 2001-08-17 | 2007-03-13 | Dsp Group Inc. | Digital front-end for wireless communication system |
US7203245B1 (en) * | 2003-03-31 | 2007-04-10 | 3Com Corporation | Symbol boundary detector method and device for OFDM systems |
US20070117523A1 (en) * | 2002-08-13 | 2007-05-24 | David Weber | Method And Apparatus For Signal Power Loss Reduction In RF Communication Systems |
US7269127B2 (en) * | 2001-10-04 | 2007-09-11 | Bae Systems Information And Electronic Systems Integration Inc. | Preamble structures for single-input, single-output (SISO) and multi-input, multi-output (MIMO) communication systems |
US7269224B2 (en) * | 2001-09-17 | 2007-09-11 | Bae Systems Information And Electronic Systems Integration Inc. | Apparatus and methods for providing efficient space-time structures for preambles, pilots and data for multi-input, multi-output communications systems |
US7282617B2 (en) * | 2005-03-31 | 2007-10-16 | Chevron U.S.A. Inc. | Process of making a highly stable aromatic alkylate suitable for use in making improved additives and surfactants |
US7286617B2 (en) * | 2002-10-21 | 2007-10-23 | Stmicroelectronics N.V. | Methods and apparatus for synchronization of training sequences |
US7352688B1 (en) * | 2002-12-31 | 2008-04-01 | Cisco Technology, Inc. | High data rate wireless bridging |
US7400643B2 (en) * | 2004-02-13 | 2008-07-15 | Broadcom Corporation | Transmission of wide bandwidth signals in a network having legacy devices |
US7423989B2 (en) * | 2004-02-13 | 2008-09-09 | Broadcom Corporation | Preamble formats for MIMO wireless communications |
US7453793B1 (en) * | 2003-04-10 | 2008-11-18 | Qualcomm Incorporated | Channel estimation for OFDM communication systems including IEEE 802.11A and extended rate systems |
US7539260B2 (en) * | 2004-05-27 | 2009-05-26 | Qualcomm Incorporated | Detecting the number of transmit antennas in wireless communication systems |
US7583746B2 (en) * | 2003-12-26 | 2009-09-01 | Kabushiki Kaisha Toshiba | Wireless transmitting and receiving device and method |
US7586884B2 (en) * | 2003-08-15 | 2009-09-08 | Qualcomm Incorporated | Joint packet detection in wireless communication system with one or more receiver |
US7599333B2 (en) * | 2005-02-08 | 2009-10-06 | Qualcomm Incorporated | Wireless messaging preambles allowing for beamforming and legacy device coexistence |
US7647069B2 (en) * | 2002-10-25 | 2010-01-12 | Nxp B.V. | Single oscillator DSSS and OFDM radio receiver |
US20100061402A1 (en) * | 2003-04-10 | 2010-03-11 | Qualcomm Incorporated | Modified preamble structure for ieee 802.11a extensions to allow for coexistence and interoperability between 802.11a devices and higher data rate, mimo or otherwise extended devices |
US8000223B2 (en) * | 2004-04-12 | 2011-08-16 | Broadcom Corporation | Method and system for multi-antenna preambles for wireless networks preserving backward compatibility |
US8218427B2 (en) * | 2003-12-27 | 2012-07-10 | Electronics And Telecommunications Research Institute | Preamble configuring method in the wireless LAN system, and a method for a frame synchronization |
Family Cites Families (44)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2970347B2 (en) | 1993-09-28 | 1999-11-02 | 住友電装株式会社 | connector |
EP0871253B1 (en) | 1993-12-06 | 2001-12-12 | Sumitomo Wiring Systems, Ltd. | Lock detection connector |
US6678310B1 (en) | 1998-01-16 | 2004-01-13 | Intersil Americas Inc | Wireless local area network spread spectrum transceiver with multipath mitigation |
CN1161900C (en) | 1999-06-28 | 2004-08-11 | 三星电子株式会社 | Apparatus and method of controlling forward link power when in discotinuous transmission mode in mobile communication system |
US7024168B1 (en) | 1999-07-07 | 2006-04-04 | Telefonaktiebolaget L M Ericsson (Publ) | Controlled antenna diversity |
JP2001292128A (en) | 2000-04-05 | 2001-10-19 | Oki Electric Ind Co Ltd | Receiver |
US20020105375A1 (en) | 2000-09-20 | 2002-08-08 | Vladislav Sorokine | Method and apparatus for detecting finger merge condition in CDMA receiver |
US7110378B2 (en) * | 2000-10-03 | 2006-09-19 | Wisconsin Alumni Research Foundation | Channel aware optimal space-time signaling for wireless communication over wideband multipath channels |
US7103115B2 (en) | 2001-05-21 | 2006-09-05 | At&T Corp. | Optimum training sequences for wireless systems |
JP3636145B2 (en) | 2001-06-15 | 2005-04-06 | ソニー株式会社 | Demodulation timing generation circuit and demodulation device |
JP3599001B2 (en) | 2001-06-25 | 2004-12-08 | ソニー株式会社 | Automatic gain control circuit and method, and demodulation device using them |
JP2003018119A (en) | 2001-06-29 | 2003-01-17 | Sony Corp | Receiver |
EP1282257A1 (en) | 2001-08-02 | 2003-02-05 | Mitsubishi Electric Information Technology Centre Europe B.V. | Method and apparatus for detecting data sequences |
US7161987B2 (en) | 2001-09-26 | 2007-01-09 | Conexant, Inc. | Single-carrier to multi-carrier wireless architecture |
JP3880358B2 (en) | 2001-10-04 | 2007-02-14 | シャープ株式会社 | OFDM demodulating circuit and OFDM receiving apparatus using the same |
JP2003163669A (en) | 2001-11-27 | 2003-06-06 | Canon Inc | Radio communication equipment |
JP3946987B2 (en) | 2001-11-28 | 2007-07-18 | インターナショナル・ビジネス・マシーンズ・コーポレーション | Multi-band communication apparatus and communication method thereof |
JP2003319005A (en) | 2002-02-20 | 2003-11-07 | Mitsubishi Electric Corp | Symbol timing correction circuit, receiver, symbol timing correction method, and demodulation process method |
DE10210236B4 (en) | 2002-03-08 | 2006-01-19 | Advanced Micro Devices, Inc., Sunnyvale | Wireless receiver synchronization |
JP4078883B2 (en) | 2002-05-29 | 2008-04-23 | ソニー株式会社 | Reception device and terminal device |
US7613248B2 (en) * | 2002-06-24 | 2009-11-03 | Qualcomm Incorporated | Signal processing with channel eigenmode decomposition and channel inversion for MIMO systems |
AU2003275040A1 (en) | 2002-09-17 | 2004-04-08 | Ipr Licensing, Inc. | Multiple pattern antenna |
JP3779673B2 (en) | 2002-10-30 | 2006-05-31 | 株式会社東芝 | Relay device and communication system |
KR100479864B1 (en) | 2002-11-26 | 2005-03-31 | 학교법인 중앙대학교 | Method and apparatus embodying and synchronizing downlink signal in mobile communication system and method for searching cell using the same |
US20040105512A1 (en) | 2002-12-02 | 2004-06-03 | Nokia Corporation | Two step synchronization procedure for orthogonal frequency division multiplexing (OFDM) receivers |
JP2004214726A (en) | 2002-12-26 | 2004-07-29 | Sony Corp | Radio communication antenna and apparatus thereof |
US20040203383A1 (en) | 2002-12-31 | 2004-10-14 | Kelton James Robert | System for providing data to multiple devices and method thereof |
JP2004289373A (en) | 2003-03-20 | 2004-10-14 | Tdk Corp | Wireless communication system, wireless terminal device, and method for switching communication system |
JP4259897B2 (en) | 2003-03-25 | 2009-04-30 | シャープ株式会社 | Wireless data transmission system and wireless data transmission / reception device |
CN100566204C (en) * | 2003-04-21 | 2009-12-02 | 三菱电机株式会社 | Radio communication device, dispensing device, receiving system and wireless communication system |
JP2004328267A (en) | 2003-04-23 | 2004-11-18 | Canon Inc | Network system and control method therefor |
JP4425857B2 (en) | 2003-06-27 | 2010-03-03 | 三菱電機株式会社 | Transmitter, receiver and wireless communication device |
US7885177B2 (en) | 2003-06-30 | 2011-02-08 | Agere Systems Inc. | Methods and apparatus for backwards compatible communication in a multiple antenna communication system using time orthogonal symbols |
US7403556B2 (en) | 2003-06-30 | 2008-07-22 | Via Technologies Inc. | Radio receiver supporting multiple modulation formats with a single pair of ADCs |
US20070087723A1 (en) | 2003-08-29 | 2007-04-19 | Hilbert Zhang | System and method for energy efficient signal detection in a wireless network device |
JP4005974B2 (en) | 2004-01-09 | 2007-11-14 | 株式会社東芝 | COMMUNICATION DEVICE, COMMUNICATION METHOD, AND COMMUNICATION SYSTEM |
US7339999B2 (en) * | 2004-01-21 | 2008-03-04 | Qualcomm Incorporated | Pilot transmission and channel estimation for an OFDM system with excess delay spread |
TW200529605A (en) | 2004-02-20 | 2005-09-01 | Airgo Networks Inc | Adaptive packet detection for detecting packets in a wireless medium |
JP2005286868A (en) * | 2004-03-30 | 2005-10-13 | Sanyo Electric Co Ltd | Receiving method and apparatus |
JP2005295239A (en) * | 2004-03-31 | 2005-10-20 | Toshiba Corp | Radio transmitter, radio receiver, radio transmission method and radio reception method |
JP4506248B2 (en) | 2004-04-02 | 2010-07-21 | ソニー株式会社 | Synchronization apparatus and synchronization method |
US7733834B2 (en) | 2004-07-19 | 2010-06-08 | Ittiam Systems (P) Ltd. | Frame detection method for 802.11b/g based WLAN systems |
JP2006197375A (en) | 2005-01-14 | 2006-07-27 | Sony Corp | Method for receiving and receiver |
US7856068B1 (en) | 2005-06-28 | 2010-12-21 | Ralink Technology Corporation | Nested preamble for multi input multi output orthogonal frequency division multiplexing |
-
2005
- 2005-05-27 HU HUE05754373A patent/HUE031812T2/en unknown
- 2005-05-27 DK DK05754373.8T patent/DK1751890T3/en active
- 2005-05-27 PT PT57543738T patent/PT1751890T/en unknown
- 2005-05-27 WO PCT/US2005/018566 patent/WO2005119922A2/en active Application Filing
- 2005-05-27 ES ES05754373.8T patent/ES2623882T3/en active Active
- 2005-05-27 PL PL05754373T patent/PL1751890T3/en unknown
- 2005-05-27 JP JP2007515341A patent/JP4838241B2/en active Active
- 2005-05-27 US US11/140,349 patent/US7599332B2/en active Active
- 2005-05-27 US US11/139,925 patent/US7539260B2/en active Active
- 2005-05-27 EP EP05754373.8A patent/EP1751890B1/en active Active
-
2009
- 2009-05-20 US US12/469,323 patent/US8457232B2/en active Active
Patent Citations (98)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5131006A (en) * | 1990-09-06 | 1992-07-14 | Ncr Corporation | Carrier detection for a wireless local area network |
US5553064A (en) * | 1994-04-05 | 1996-09-03 | Stanford Telecommunications, Inc. | High speed bidirectional digital cable transmission system |
US5694421A (en) * | 1995-03-17 | 1997-12-02 | Samsung Electronics Co., Ltd. | Frequency-selective interference signal detecting apparatus and method thereof |
US6452981B1 (en) * | 1996-08-29 | 2002-09-17 | Cisco Systems, Inc | Spatio-temporal processing for interference handling |
US6144711A (en) * | 1996-08-29 | 2000-11-07 | Cisco Systems, Inc. | Spatio-temporal processing for communication |
US6055231A (en) * | 1997-03-12 | 2000-04-25 | Interdigital Technology Corporation | Continuously adjusted-bandwidth discrete-time phase-locked loop |
US6226508B1 (en) * | 1997-07-04 | 2001-05-01 | Matsushita Electric Industrial Co., Ltd. | Transmission diversity apparatus |
US6118806A (en) * | 1998-05-29 | 2000-09-12 | Kdd Corporation | Signal synthesis method and apparatus under diversity reception |
US6304750B1 (en) * | 1998-11-06 | 2001-10-16 | Lucent Technologies Inc. | Space-time diversity receiver for wireless systems |
US6757322B2 (en) * | 1998-11-24 | 2004-06-29 | Linex Technologies, Inc. | Space diversity and coding, spread-spectrum antenna and method |
US6563460B2 (en) * | 1999-01-08 | 2003-05-13 | Trueposition, Inc. | Collision recovery in a wireless location system |
US6260167B1 (en) * | 1999-02-23 | 2001-07-10 | Advanced Micro Devices, Inc. | Apparatus and method for deterministic receiver testing |
US20050018754A1 (en) * | 1999-03-15 | 2005-01-27 | Lg Electronics Inc. | Pilot signals for synchronization and/or channel estimation |
US6690715B2 (en) * | 1999-06-29 | 2004-02-10 | Intersil Americas Inc. | Rake receiver with embedded decision feedback equalizer |
US20010033603A1 (en) * | 2000-01-21 | 2001-10-25 | Microgistics, Inc. | Spread spectrum burst signal receiver and related methods |
US6473467B1 (en) * | 2000-03-22 | 2002-10-29 | Qualcomm Incorporated | Method and apparatus for measuring reporting channel state information in a high efficiency, high performance communications system |
US20020012411A1 (en) * | 2000-04-05 | 2002-01-31 | Johann Heinzl | Global positioning system receiver capable of functioning in the presence of interference |
US6934323B2 (en) * | 2000-07-10 | 2005-08-23 | Mitsubishi Denki Kabushiki Kaisha | Adaptive array antenna-based CDMA receiver that can find the weight vectors with a reduced amount of calculations |
US6661857B1 (en) * | 2000-07-10 | 2003-12-09 | Intersil Americas Inc. | Rapid estimation of wireless channel impulse response |
US20020122511A1 (en) * | 2000-09-01 | 2002-09-05 | Alan Kwentus | Satellite receiver |
US20020163933A1 (en) * | 2000-11-03 | 2002-11-07 | Mathilde Benveniste | Tiered contention multiple access (TCMA): a method for priority-based shared channel access |
US20020118635A1 (en) * | 2000-11-13 | 2002-08-29 | Nee Didier Johannes R. Van | Communication system |
US20030236108A1 (en) * | 2000-11-15 | 2003-12-25 | Jiang Li | Spatial domain matched filtering method and array receiver in wireless communication system |
US7106709B2 (en) * | 2000-11-29 | 2006-09-12 | Telefonaktiebologet Lm Ericsson (Publ) | Timing drift compensation in wireless packet-based systems |
US7082159B2 (en) * | 2000-11-29 | 2006-07-25 | Telefonaktiebolaget Lm Ericsson (Publ) | Methods and arrangements in a telecommunications system |
US20020065047A1 (en) * | 2000-11-30 | 2002-05-30 | Moose Paul H. | Synchronization, channel estimation and pilot tone tracking system |
US6670310B2 (en) * | 2000-12-12 | 2003-12-30 | Cleveland Punch And Die Co | High performance lubricant for metal punching and shearing |
US20020111142A1 (en) * | 2000-12-18 | 2002-08-15 | Klimovitch Gleb V. | System, apparatus, and method of estimating multiple-input multiple-output wireless channel with compensation for phase noise and frequency offset |
US7006040B2 (en) * | 2000-12-21 | 2006-02-28 | Hitachi America, Ltd. | Steerable antenna and receiver interface for terrestrial broadcast |
US20020101825A1 (en) * | 2001-01-30 | 2002-08-01 | Beck Eric C. | Optimal channel sounding system |
US20020160737A1 (en) * | 2001-03-06 | 2002-10-31 | Magis Networks, Inc. | Method and apparatus for diversity antenna branch selection |
US20040116112A1 (en) * | 2001-03-08 | 2004-06-17 | Gray Steven D. | Apparatus, and associated method, for reporting a measurement summary in a radio communication system |
US7088782B2 (en) * | 2001-04-24 | 2006-08-08 | Georgia Tech Research Corporation | Time and frequency synchronization in multi-input, multi-output (MIMO) systems |
US7177369B2 (en) * | 2001-04-27 | 2007-02-13 | Vivato, Inc. | Multipath communication methods and apparatuses |
US20030012160A1 (en) * | 2001-07-06 | 2003-01-16 | Webster Mark A. | Wireless communication system configured to communicate using a mixed waveform configuration |
US7123662B2 (en) * | 2001-08-15 | 2006-10-17 | Mediatek Inc. | OFDM detection apparatus and method for networking devices |
US7190748B2 (en) * | 2001-08-17 | 2007-03-13 | Dsp Group Inc. | Digital front-end for wireless communication system |
US7269224B2 (en) * | 2001-09-17 | 2007-09-11 | Bae Systems Information And Electronic Systems Integration Inc. | Apparatus and methods for providing efficient space-time structures for preambles, pilots and data for multi-input, multi-output communications systems |
US7184495B2 (en) * | 2001-09-24 | 2007-02-27 | Atheros Communications, Inc. | Efficient pilot tracking method for OFDM receivers |
US20040048574A1 (en) * | 2001-09-26 | 2004-03-11 | General Atomics | Method and apparatus for adapting multi-band ultra-wideband signaling to interference sources |
US7269127B2 (en) * | 2001-10-04 | 2007-09-11 | Bae Systems Information And Electronic Systems Integration Inc. | Preamble structures for single-input, single-output (SISO) and multi-input, multi-output (MIMO) communication systems |
US20030072255A1 (en) * | 2001-10-17 | 2003-04-17 | Jianglei Ma | System access and synchronization methods for MIMO OFDM communications systems and physical layer packet and preamble design |
US7106784B2 (en) * | 2002-01-25 | 2006-09-12 | Sasken Communication Technologies Limited | Universal rake receiver |
US20040030530A1 (en) * | 2002-01-30 | 2004-02-12 | Kuo-Hui Li | Apparatus and method for detection of direct sequence spread spectrum signals in networking systems |
US7161996B1 (en) * | 2002-02-05 | 2007-01-09 | Airgo Networks, Inc. | Multi-antenna wireless receiver chains with vector decoding |
US7945007B2 (en) * | 2002-02-05 | 2011-05-17 | Qualcomm, Incorporated | Multi-antenna wireless receiver chains with vector decoding |
US7561646B2 (en) * | 2002-02-05 | 2009-07-14 | Qualcomm Incorporated | Multi-antenna wireless receiver chains with vector decoding |
US20030153275A1 (en) * | 2002-02-14 | 2003-08-14 | Interdigital Technology Corporation | Wireless communication system having adaptive threshold for timing deviation measurement and method |
US20060013327A1 (en) * | 2002-03-01 | 2006-01-19 | Ipr Licensing, Inc. | Apparatus for antenna diversity using joint maximal ratio combining |
US20040052231A1 (en) * | 2002-03-18 | 2004-03-18 | Kumar Ramaswamy | Method and apparatus for indicating the presence of a wireless local area network by detecting signature sequences |
US20040001430A1 (en) * | 2002-04-18 | 2004-01-01 | Gardner Steven H. | Method and apparatus for preamble detection and time synchronization estimation in OFDM communication systems |
US20030210646A1 (en) * | 2002-05-10 | 2003-11-13 | Kddi Corporation | Frequency error correction device and OFDM receiver with the device |
US20040005018A1 (en) * | 2002-07-03 | 2004-01-08 | Oki Techno Centre (Singapore) Pte Ltd | Receiver and method for WLAN burst type signals |
US20040071104A1 (en) * | 2002-07-03 | 2004-04-15 | Commasic, Inc. | Multi-mode method and apparatus for performing digital modulation and demodulation |
US20040005022A1 (en) * | 2002-07-03 | 2004-01-08 | Oki Techno Centre (Singapore) Pte Ltd. | Receiver and method for WLAN burst type signals |
US20070117523A1 (en) * | 2002-08-13 | 2007-05-24 | David Weber | Method And Apparatus For Signal Power Loss Reduction In RF Communication Systems |
US20040032825A1 (en) * | 2002-08-19 | 2004-02-19 | Halford Steven D. | Wireless receiver for sorting packets |
US20040114546A1 (en) * | 2002-09-17 | 2004-06-17 | Nambirajan Seshadri | System and method for providing a mesh network using a plurality of wireless access points (WAPs) |
US7286617B2 (en) * | 2002-10-21 | 2007-10-23 | Stmicroelectronics N.V. | Methods and apparatus for synchronization of training sequences |
US7647069B2 (en) * | 2002-10-25 | 2010-01-12 | Nxp B.V. | Single oscillator DSSS and OFDM radio receiver |
US20040100939A1 (en) * | 2002-11-26 | 2004-05-27 | Kriedte Kai Roland | Symbol timing for MIMO OFDM and other wireless communication systems |
US20040120428A1 (en) * | 2002-12-18 | 2004-06-24 | Maltsev Alexander A. | Adaptive channel estimation for orthogonal frequency division multiplexing systems or the like |
US20040161046A1 (en) * | 2002-12-23 | 2004-08-19 | International Business Machines Corporation | Acquisition and adjustment of gain, receiver clock frequency, and symbol timing in an OFDM radio receiver |
US7352688B1 (en) * | 2002-12-31 | 2008-04-01 | Cisco Technology, Inc. | High data rate wireless bridging |
US20040198265A1 (en) * | 2002-12-31 | 2004-10-07 | Wallace Bradley A. | Method and apparatus for signal decoding in a diversity reception system with maximum ratio combining |
US20040190560A1 (en) * | 2003-03-28 | 2004-09-30 | Maltsev Alexander A. | Receiver and method to detect and synchronize with a symbol boundary of an OFDM symbol |
US7203245B1 (en) * | 2003-03-31 | 2007-04-10 | 3Com Corporation | Symbol boundary detector method and device for OFDM systems |
US20050002327A1 (en) * | 2003-04-07 | 2005-01-06 | Shaolin Li | Single chip multi-antenna wireless data processor |
US20040204026A1 (en) * | 2003-04-09 | 2004-10-14 | Ar Card | Method, apparatus and system of configuring a wireless device based on location |
US20050233709A1 (en) * | 2003-04-10 | 2005-10-20 | Airgo Networks, Inc. | Modified preamble structure for IEEE 802.11a extensions to allow for coexistence and interoperability between 802.11a devices and higher data rate, MIMO or otherwise extended devices |
US20100061402A1 (en) * | 2003-04-10 | 2010-03-11 | Qualcomm Incorporated | Modified preamble structure for ieee 802.11a extensions to allow for coexistence and interoperability between 802.11a devices and higher data rate, mimo or otherwise extended devices |
US7453793B1 (en) * | 2003-04-10 | 2008-11-18 | Qualcomm Incorporated | Channel estimation for OFDM communication systems including IEEE 802.11A and extended rate systems |
US20040240402A1 (en) * | 2003-05-27 | 2004-12-02 | Stephens Adrian P. | Multiple mode support in a wireless local area network |
US20040242273A1 (en) * | 2003-05-30 | 2004-12-02 | Corbett Christopher J. | Using directional antennas to enhance throughput in wireless networks |
US20040258025A1 (en) * | 2003-06-18 | 2004-12-23 | University Of Florida | Wireless lan compatible multi-input multi-output system |
US20040266375A1 (en) * | 2003-06-27 | 2004-12-30 | Qinghua Li | Switching schemes for multiple antennas |
US20050030886A1 (en) * | 2003-08-07 | 2005-02-10 | Shiquan Wu | OFDM system and method employing OFDM symbols with known or information-containing prefixes |
US7586884B2 (en) * | 2003-08-15 | 2009-09-08 | Qualcomm Incorporated | Joint packet detection in wireless communication system with one or more receiver |
US8023397B2 (en) * | 2003-08-15 | 2011-09-20 | Qualcomm Incorporated | Joint packet detection in a wireless communication system with one or more receivers |
US20050047384A1 (en) * | 2003-08-27 | 2005-03-03 | Wavion Ltd. | WLAN capacity enhancement using SDM |
US20050152314A1 (en) * | 2003-11-04 | 2005-07-14 | Qinfang Sun | Multiple-input multiple output system and method |
US20050105460A1 (en) * | 2003-11-19 | 2005-05-19 | Samsung Electronics Co., Ltd. | Apparatus and method for generating a preamble sequence in an orthogonal frequency division multiplexing communication system |
US7583746B2 (en) * | 2003-12-26 | 2009-09-01 | Kabushiki Kaisha Toshiba | Wireless transmitting and receiving device and method |
US8218427B2 (en) * | 2003-12-27 | 2012-07-10 | Electronics And Telecommunications Research Institute | Preamble configuring method in the wireless LAN system, and a method for a frame synchronization |
US7400643B2 (en) * | 2004-02-13 | 2008-07-15 | Broadcom Corporation | Transmission of wide bandwidth signals in a network having legacy devices |
US20050180353A1 (en) * | 2004-02-13 | 2005-08-18 | Hansen Christopher J. | MIMO wireless communication greenfield preamble formats |
US7423989B2 (en) * | 2004-02-13 | 2008-09-09 | Broadcom Corporation | Preamble formats for MIMO wireless communications |
US7599332B2 (en) * | 2004-04-05 | 2009-10-06 | Qualcomm Incorporated | Modified preamble structure for IEEE 802.11a extensions to allow for coexistence and interoperability between 802.11a devices and higher data rate, MIMO or otherwise extended devices |
US8000223B2 (en) * | 2004-04-12 | 2011-08-16 | Broadcom Corporation | Method and system for multi-antenna preambles for wireless networks preserving backward compatibility |
US20050237992A1 (en) * | 2004-04-15 | 2005-10-27 | Airgo Networks, Inc. | Packet concatenation in wireless networks |
US7539260B2 (en) * | 2004-05-27 | 2009-05-26 | Qualcomm Incorporated | Detecting the number of transmit antennas in wireless communication systems |
US20050281241A1 (en) * | 2004-06-22 | 2005-12-22 | Webster Mark A | Legacy compatible spatial multiplexing systems and methods |
US20060034389A1 (en) * | 2004-08-12 | 2006-02-16 | Tsuguhide Aoki | Wireless transmitting device and method |
US20060088120A1 (en) * | 2004-10-26 | 2006-04-27 | Hansen Christopher J | Mixed mode preamble for MIMO wireless communications |
US7599333B2 (en) * | 2005-02-08 | 2009-10-06 | Qualcomm Incorporated | Wireless messaging preambles allowing for beamforming and legacy device coexistence |
US7282617B2 (en) * | 2005-03-31 | 2007-10-16 | Chevron U.S.A. Inc. | Process of making a highly stable aromatic alkylate suitable for use in making improved additives and surfactants |
US20060270364A1 (en) * | 2005-05-31 | 2006-11-30 | Tsuguhide Aoki | Wireless packet transmitting device and method using a plurality of antennas |
US20060281487A1 (en) * | 2005-06-09 | 2006-12-14 | Girardeau James W Jr | Increased data rate transmissions of a wireless communication |
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100061402A1 (en) * | 2003-04-10 | 2010-03-11 | Qualcomm Incorporated | Modified preamble structure for ieee 802.11a extensions to allow for coexistence and interoperability between 802.11a devices and higher data rate, mimo or otherwise extended devices |
US8611457B2 (en) | 2003-04-10 | 2013-12-17 | Qualcomm Incorporated | Modified preamble structure for IEEE 802.11A extensions to allow for coexistence and interoperability between 802.11A devices and higher data rate, MIMO or otherwise extended devices |
US8743837B2 (en) | 2003-04-10 | 2014-06-03 | Qualcomm Incorporated | Modified preamble structure for IEEE 802.11A extensions to allow for coexistence and interoperability between 802.11A devices and higher data rate, MIMO or otherwise extended devices |
US8457232B2 (en) * | 2004-05-27 | 2013-06-04 | Qualcomm Incorporated | Detecting the number of transmit antennas in wireless communication systems |
US20140219264A1 (en) * | 2004-10-26 | 2014-08-07 | Broadcom Corporation | Method and system for compromise greenfield preambles for 802.11n |
US8964521B2 (en) * | 2004-10-26 | 2015-02-24 | Broadcom Corporation | Method and system for compromise greenfield preambles for 802.11N |
US20150124794A1 (en) * | 2004-10-26 | 2015-05-07 | Broadcom Corporation | Method and system for compromise greenfield preambles for 802.11n |
US9191092B2 (en) * | 2004-10-26 | 2015-11-17 | Broad Corporation | Method and system for compromise greenfield preambles for 802.11n |
US20060182017A1 (en) * | 2005-02-16 | 2006-08-17 | Hansen Christopher J | Method and system for compromise greenfield preambles for 802.11n |
US8737189B2 (en) * | 2005-02-16 | 2014-05-27 | Broadcom Corporation | Method and system for compromise greenfield preambles for 802.11n |
CN109873781A (en) * | 2017-12-01 | 2019-06-11 | 晨星半导体股份有限公司 | Meet the signal receiving device and its signal processing method of multimedia over Coax Alliance standards |
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DK1751890T3 (en) | 2017-06-12 |
PL1751890T3 (en) | 2017-08-31 |
PT1751890T (en) | 2017-05-24 |
JP4838241B2 (en) | 2011-12-14 |
EP1751890B1 (en) | 2017-03-01 |
EP1751890A4 (en) | 2012-10-17 |
WO2005119922A3 (en) | 2006-06-15 |
EP1751890A2 (en) | 2007-02-14 |
JP2008500783A (en) | 2008-01-10 |
US20050271157A1 (en) | 2005-12-08 |
ES2623882T3 (en) | 2017-07-12 |
HUE031812T2 (en) | 2017-08-28 |
US7599332B2 (en) | 2009-10-06 |
WO2005119922A2 (en) | 2005-12-15 |
US7539260B2 (en) | 2009-05-26 |
US8457232B2 (en) | 2013-06-04 |
US20050286474A1 (en) | 2005-12-29 |
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